Cornerstone Incident History

1. postmortemSep 6 · 18:44 UTC

   **Root Cause Analysis**   **Incident Summary:** On August 25th, 2026, an issue was identified affecting select customers using the China Content Delivery Network \(CDN\). The issue impacted requests for specific web resources across US SL1, US SL5, FRA SL1, JP SL1, and AU SL 1 Production environments. **Impact:** Affected users experienced errors when accessing certain resources through the China CDN during the incident window. The impact was limited to customers using the China CDN. **Root Cause:** The issue was caused by a configuration optimization implemented to improve resource caching behavior. The change resulted in an unexpected routing condition, which caused an incorrect SSL certificate to be presented for affected requests. As a result, requests for the impacted resources were rejected and returned errors to users. **Resolution:** The configuration was reverted to the previous stable state, which removed the unexpected routing condition and restored the correct SSL configuration. Following the change, the affected resources were validated and service was restored for the impacted customers. **Preventive Measures:** * Additional validation will be performed for CDN configuration changes to confirm correct routing and SSL behavior before and after implementation * Configuration changes impacting CDN caching and routing will undergo additional review prior to implementation

Reported by Cornerstone on their status page.

1. postmortemSep 6 · 18:24 UTC

   **Root Cause Analysis** ‌ **Incident Summary:** On August 28th, 2026, users in the FRA SL1 Production environment experienced intermittent issues accessing Career Site functionalities. **Impact:** Intermittent failures while accessing Career Site functionality, resulting in a degraded user experience and partial service disruption during the incident window. **Root Cause:** The issue was caused by a sudden increase in traffic that temporarily exceeded the available service capacity. During the resulting scale-up activity, newly provisioned application capacity required additional time to become fully operational and could not immediately accommodate the increased demand. The limited capacity buffer combined with the application startup time resulted in intermittent service failures until sufficient capacity was available to handle the traffic. **Resolution:** The service capacity and scaling configuration were adjusted to maintain an appropriate capacity buffer and better accommodate sudden increases in traffic. The affected service was also redeployed to restore stability. **Preventive Measures:** * Application startup and initialization processes will be optimized to reduce the time required for newly provisioned capacity to become fully operational * Baseline capacity and scaling thresholds will be reviewed and optimized to maintain sufficient buffer for sudden increases in traffic * Capacity and application health will continue to be monitored during traffic fluctuations to ensure sufficient resources are available to maintain service stability

Reported by Cornerstone on their status page.

1. postmortemSep 6 · 18:17 UTC

   **Root Cause Analysis**   **Incident Summary:** On August 27th, 2026, users in the CDG SL1 Production environment experienced intermittent issues accessing Career Site functionalities. **Impact:** Intermittent failures while accessing Career Site functionality, resulting in a degraded user experience and partial service disruption during the incident window. **Root Cause:** The issue was caused by a sudden increase in traffic that temporarily exceeded the available service capacity. During the resulting scale-up activity, newly provisioned application capacity required additional time to become fully operational and could not immediately accommodate the increased demand. The limited capacity buffer combined with the application startup time resulted in intermittent service failures until sufficient capacity was available to handle the traffic. **Resolution:** The service capacity and scaling configuration were adjusted to maintain an appropriate capacity buffer and better accommodate sudden increases in traffic. The affected service was also redeployed to restore stability. **Preventive Measures:** * Application startup and initialization processes will be optimized to reduce the time required for newly provisioned capacity to become fully operational * Baseline capacity and scaling thresholds will be reviewed and optimized to maintain sufficient buffer for sudden increases in traffic * Capacity and application health will continue to be monitored during traffic fluctuations to ensure sufficient resources are available to maintain service stability

Reported by Cornerstone on their status page.

1. resolvedSep 5 · 03:44 UTC

   After a period of monitoring with no repeat occurrences we are marking this incident Resolved. A formal Root Cause Analysis will be available 7-10 business days from Resolution.

Reported by Cornerstone on their status page.

1. resolvedSep 3 · 16:12 UTC

   This incident has been resolved.

Reported by Cornerstone on their status page.

1. postmortemSep 3 · 14:55 UTC

   **Issue Summary:** Starting August 20, 2026, users in the UK Production, Pilot, and Stage environments, including Metpol Production and Pilot, experienced disruption affecting Edge Import functionality. **Root Cause:** The issue occurred during a scheduled cleanup activity when the associated cleanup jobs failed across the affected environments. The failed jobs contributed to instability within the supporting services, which impacted Edge Import availability and processing. **Corrective Action:** Cornerstone reviewed the affected service environments and reset the associated capacity to restore service stability. Once the services had recovered, the cleanup jobs were successfully re-run. The affected environments were then monitored to confirm that service health and Edge Import functionality had returned to normal. **Preventive Measures:** To reduce the risk of a similar issue, Cornerstone has taken the following action: * Strengthened post-maintenance validation to confirm service health before and after scheduled cleanup activities.

Reported by Cornerstone on their status page.

1. postmortemSep 3 · 14:31 UTC

   **Issue Summary:** On August 24, 2026, users in the US SL5 Production environment experienced significant latency across multiple portals. The issue resulted in elevated response times and degraded portal responsiveness for affected users. **Root Cause:** The issue was caused by a degraded execution plan associated with a high-frequency database operation. The change in execution behavior caused the operation to consume significantly more database resources than expected, resulting in elevated CPU utilization and increased latency across the environment. Concurrent high-volume workloads further contributed to resource contention during the incident and amplified the overall performance impact. **Corrective Action:** Cornerstone cleared the problematic cached execution plans and recompiled the affected database procedure to generate a new execution plan. Additional workload was temporarily controlled to reduce resource consumption while the environment recovered. Following these actions, database utilization decreased, portal response times improved, and the environment returned to normal performance levels. **Preventive Measures:** To reduce the risk of a similar issue, Cornerstone has taken the following actions: * Reviewing execution plan behavior for the identified high-frequency database operation to reduce the likelihood of future plan degradation. * Reviewing high-volume workloads and their resource consumption to reduce the risk of excessive database contention during periods of elevated activity.

Reported by Cornerstone on their status page.

1. resolvedSep 3 · 12:56 UTC

   This incident has been resolved.

Reported by Cornerstone on their status page.

1. resolvedSep 3 · 05:00 UTC

   The CSOD Technology Team observed an issue affecting Edge Import on FRA and CDG swimlanes. The problem began on September 2nd 2026, at 10:00 PM Pacific Time and was resolved on September 2nd 2026, at 11:30 PM Pacific Time. During this time, clients may have experienced issues or delays with Edge Import functionalities.

Reported by Cornerstone on their status page.

1. resolvedSep 1 · 14:43 UTC

   The CSOD Technology Team observed a service disruption on US SL5. The issue began at 6:47 AM Pacific Time and service was restored at 6:56 AM Pacific Time. During this time, clients with portals on this swimlane were unable to access the application. Following a brief period of monitoring, the fix remains stable and the service continues to operate as expected.

Reported by Cornerstone on their status page.

1. postmortemSep 1 · 06:47 UTC

   **Root Cause Analysis** ‌ **Incident Summary:** On August 20th, 2026, users in the UK Production and Pilot environments, across all swimlanes, experienced issues creating VILT sessions. **Impact:** Users were unable to create VILT sessions, resulting in temporary disruption to VILT-related functionality. **Root Cause:** The issue was related to the availability of the required messaging queues used by the VILT integration service. The queues were not available as expected, resulting in exceptions and preventing the service from processing VILT requests successfully. **Resolution:** The VILT integration service was redeployed in the UK Production and Pilot environments. Following the redeployment, the required queues were successfully established and the exceptions stopped. VILT session creation functionality was restored. **Preventive Measures:** * Queue availability and service startup dependencies are being reviewed to ensure the required queues are available during service initialization * Startup and redeployment sequencing are being reviewed to prevent similar queue initialization issues in the future

Reported by Cornerstone on their status page.

1. postmortemSep 1 · 06:37 UTC

   **Root Cause Analysis**   **Incident Summary:** On August 19th, 2026, users in the EU Production environment experienced intermittent issues accessing Career Site functionalities. **Impact:** Users experienced intermittent failures while accessing Career Site functionality, resulting in degraded user experience and partial service disruption during the incident window. **Root Cause:** The issue was caused by a sudden increase in traffic that temporarily exceeded the available service capacity during scaling activity. Due to the service's sensitivity to startup time, the newly provisioned capacity was unable to stabilize quickly enough to handle the increased traffic. This resulted in intermittent service failures. **Resolution:** The service capacity and scaling configuration were adjusted to maintain sufficient baseline capacity and better accommodate sudden increases in traffic. The affected service was also redeployed to restore stability. **Preventive Measures:** * Scaling configuration has been optimized to better respond to sudden traffic increases * Additional capacity and startup behavior are being monitored to reduce the likelihood of recurrence

Reported by Cornerstone on their status page.

1. postmortemSep 1 · 06:29 UTC

   Root Cause Analysis ‌ **Incident Summary:** On August 17th, 2026, customers across US Production environments experienced issues logging in due to Multi-Factor Authentication \(MFA\) failures. Affected users were unable to complete the authentication process and access the application. **Impact:** Users across US Production environments experienced intermittent login failures due to unavailability of the MFA service. **Root Cause:** The issue was caused by insufficient memory allocation for the MFA service. Service tasks became unstable and were repeatedly terminated due to memory exhaustion, resulting in no healthy endpoints being available to process authentication requests. **Resolution:** Additional capacity was provisioned; however, the service continued to experience memory-related instability. The memory allocation for the service was subsequently increased, after which the service tasks stabilized and healthy endpoints became available. Login functionality was restored. **Preventive Measures:** * Service resource utilization and memory requirements were reviewed to ensure appropriate capacity is maintained * Additional health checks will be incorporated to help identify potential service degradation before it impacts customer authentication * Resource requirements will be reviewed as part of future capacity planning and scaling activities

Reported by Cornerstone on their status page.

1. resolvedAug 19 · 13:00 UTC

   The CSOD Technology Team identified and resolved an issue impacting access to Imports and Feeds in Edge, which caused loading failures, navigation errors, and, in some cases, automatic disabling of the CHR > Employee Load Enablement setting. The problem observed at August 19, 2026, 9:00 AM PT, and full functionality was restored as of August 19, 2026, 12:10 PM PT.

Reported by Cornerstone on their status page.

1. postmortemAug 18 · 15:21 UTC

   **Incident Summary** Starting August 10th, 2026, users in the US RES PRD environment experienced intermittent issues with user management functionality and other portal functions dependent on core user services.   **Impact** Affected users were intermittently unable to edit user records and may have experienced timeouts or errors when accessing other functionality dependent on core user services. The impact was limited to requests routed through the affected capacity, while healthy capacity continued to serve requests normally.   **Root Cause Analysis \(RCA\)** The issue was related to instability affecting a subset of application capacity. Multiple services became unhealthy on the affected nodes, resulting in intermittent request failures and timeouts for functionality dependent on those services. The remaining healthy capacity continued to serve requests normally.   **Resolution** The affected nodes were identified and recycled to restore service health. Following the recovery actions, the affected services returned to a healthy state and intermittent timeout issues were resolved.   **Preventive Measures** * Monitoring and alerting for unhealthy application capacity will continue to be reviewed to ensure timely identification and remediation of similar conditions. * Post-recovery validation will be performed to confirm that affected capacity has returned to a healthy state before normal traffic handling is resumed.

Reported by Cornerstone on their status page.

1. postmortemAug 18 · 15:11 UTC

   **Incident Summary** Starting August 10th, 2026, users experienced intermittent issues accessing the Career Site in the Frankfurt \(EU\), FR EXT\(CDG\) , FR RES\(CDG\) and UK \(all swimlanes\) Production environment.   **Impact** Users experienced intermittent access failures and degraded responsiveness while accessing the Career Site during the incident window.   **Root Cause Analysis \(RCA\)** The issue was related to an environment change that resulted in reduced available application capacity during EMEA region business hours. The newly provisioned capacity was not available as expected, which placed increased load on the existing application capacity. This resulted in instability and intermittent request failures affecting the Career Site.   **Resolution** The environment was stabilized by restoring the required application capacity and reverting the changes contributing to the instability. Following the recovery actions, application stability was restored and Career Site access returned to normal.   **Preventive Measures** * Post-change validation will be strengthened to confirm that newly provisioned capacity is fully available before changes are considered complete. * Capacity and application health will be monitored following environment changes, particularly during business hours, to identify similar conditions earlier.

Reported by Cornerstone on their status page.

1. postmortemAug 18 · 15:00 UTC

   **Incident Summary** Starting August 10th, 2026, users experienced intermittent issues accessing the Career Site in the Frankfurt \(EU\), FR EXT\(CDG\) , FR RES\(CDG\) and UK \(all swimlanes\) Production environment.   **Impact** Users experienced intermittent access failures and degraded responsiveness while accessing the Career Site during the incident window.   **Root Cause Analysis \(RCA\)** The issue was related to an environment change that resulted in reduced available application capacity during EMEA region business hours. The newly provisioned capacity was not available as expected, which placed increased load on the existing application capacity. This resulted in instability and intermittent request failures affecting the Career Site.   **Resolution** The environment was stabilized by restoring the required application capacity and reverting the changes contributing to the instability. Following the recovery actions, application stability was restored and Career Site access returned to normal.   **Preventive Measures** * Post-change validation will be strengthened to confirm that newly provisioned capacity is fully available before changes are considered complete. * Capacity and application health will be monitored following environment changes, particularly during business hours, to identify similar conditions earlier.

Reported by Cornerstone on their status page.

1. postmortemAug 13 · 08:26 UTC

   **Root Cause Analysis** ‌ **Issue Summary:** There are backend processes in place that are designed to handle course and subscription updates reliably, without causing delays in downstream processing. During the incident, a very large update covering many courses created a backlog in the processing system, which led to delayed updates from reaching downstream services. **Root Cause:** The disruption happened because an oversized bulk update was allowed to proceed, and the available safeguards were not strong enough to prevent it from overwhelming the processing queues. As a result, the system spent more time working through the backlog than processing new changes, delaying course update propagation downstream. The incident recurred because user behavior alone was not a reliable control, and enforcement of prior guidance was not sufficient. **Corrective Action:** On July 21st, 2026, Cornerstone Engineering placed a block to prevent further incoming events of a specific type from entering the queue. Following that action, Cornerstone Engineering ran an emergency data fix to stop processing already queued items, helping the system recover faster and reducing the backlog’s impact. **Preventive Action:**  * Implemented stronger permission controls so only super admin users can perform high-impact actions such as approving, bulk approving, bulk uploading, and publishing subscriptions * Updated the emergency script to support running within a specific date range and made it more widely available across our teams * Updated our emergency runbook for queue overload incidents, so response is faster and more consistent next time

Reported by Cornerstone on their status page.