beta/security/auditLog/queries — Intermittent 500 on create, 404 on poll for a query that was just successfully created

We are using the Microsoft Graph beta API (AuditLogsQuery.Read.All permission) to create and poll audit log queries. This API has been working for us for an extended period. We started observing this issue at the beginning of this week (around April 7, 2026). No changes were made on our side same app registration, same permissions, same code.

Observed behavior:

1. POST /beta/security/auditLog/queries → intermittent HTTP 500 with code: "UnknownError" and empty message (not always, sometimes succeeds)
2. When POST succeeds and returns a valid query ID, we repeatedly poll GET /beta/security/auditLog/queries/{id} at regular intervals, every single attempt returns HTTP 404 with code: "UnknownError". The query never becomes reachable.

Request body used for POST:

{
    "displayName" : "manual-test-entra",
    "filterStartDateTime": "2026-02-28T00:00:00Z",
    "filterEndDateTime" : "2026-03-04T00:00:00Z",
    "operationFilters" : [ "Add member to role.",
			"Add user.",
			"Consent to application.",
			"Delete user.",
			"Remove member from role.",
			"Update user.",
			"UserLoggedIn",
			"UserLoginFailed"
	]
}

Actual response received on GET 404:

{
    "error": {
        "code": "UnknownError",
        "message": "",
        "innerError": {
            "date": "2026-04-07T15:48:01",
            "request-id": "6ffd2e59-a063-44ea-b776-9a369920848b",
            "client-request-id": "6ffd2e59-a063-44ea-b776-9a369920848b"
        }
    }
}

Questions:

1. Was there a service change or incident on the beta/security/auditLog/queries endpoint around April 7, 2026?                                                                                         

 2. Is there a known replication delay between write and read on this endpoint?

 3. Is there a recommended retry/backoff strategy for polling after a successful create?