OneNote copyToNotebook returns 202 but the operation stays at "not started" forever (Graph v1.0)

We are calling the OneNote copy API from a scheduled automation and since around

2026-10-20 the copy operations are accepted but never executed.

CALL

POST https://graph.microsoft.com/v1.0/groups/{sourceGroupId}/onenote/sections/{sectionId}/copyToNotebook

Body: { "groupId": "<target group id>", "id": "<target notebook id>" }

Auth: delegated token (Notes.ReadWrite.All, admin consented)

WHAT HAPPENS

The request returns HTTP 202 with a valid onenoteOperation. Polling the operation

returns status "not started" indefinitely - we tracked single operations for more

than 24 hours and polled one continuously for 200+ seconds. No error is ever

reported, and the section never appears in the destination notebook.

Roughly 70 copy requests were submitted against the same destination notebook over

24 hours. None of them executed.

WHAT WE ALREADY RULED OUT

1. The destination notebook is fine. POST /groups/{id}/onenote/notebooks/{nb}/sections creates a section instantly and it can be read back immediately.
2. Permissions are fine. The API validates synchronously - copying onto an existing section name is correctly rejected with 409 / error 20117.
3. Polling is correct. GET /groups/{source}/onenote/operations/{opId} returns the operation record, not a 404.
4. Not app-only related - we use delegated tokens only.
5. The nested path /onenote/notebooks/{nbId}/sections/{secId}/copyToNotebook does not exist server-side (404).

CORRELATION IDS (2026-10-26)

operation ids: copy-40ecbaa6-8129-444d-9d4e-ee111a2a56d4

           copy-c8670b1f-3c8b-4da4-a9b4-f8fc112a0332

request-ids : 6d9f15bd-cac5-40f0-b74d-f67652e7171b

           44787818-954a-486d-9bb0-b156f5afc926

data centers : Germany West Central, Central US

QUESTIONS

1. Why are these operations accepted but never scheduled for execution?
2. Is there a per-notebook or per-tenant copy queue that can get stuck, and can it be reset?