Microsoft 365 Alert – Service Degradation – Microsoft Defender XDR – Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query – ONGOING

Announcements Sharmista Mohanta

24/08/2026 09:26:00 AM

NHS.net Connect Reference: INC46916773

Microsoft Reference: DZ1459263

Issue Status: ONGOING

Issue Description: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

More info: The issue is specifically happening when using “$Select” as part of the query.

Affected users can bypass the issue by not using “$Select” in the queries.

Current Update: 24/08/2026 09:27:00 AM – Based on Microsoft’s analysis, they have determined that the code fix will take an extended amount of time to deploy to the affected environment. They are monitoring the progress and currently estimate that the fix will reach all affected environments by the middle of September 2026.

Scope of impact: This issue may impact any user querying the Microsoft Graph Attack Simulation Training API with $Select OData in Microsoft Defender. This section may be updated as our investigation continues.

Root cause: A code regression after a recent services update is impacting OData $Select query, causing failures.

Next update by: Wednesday, August 26, 2026, at 6:00 AM UTC