403 when setting publish_to_category topic timer after update

Contribute Bug
,
1

After a recent core update, one of our global moderators can no longer use Schedule Publishing / Publish to Category on a topic timer.

Workflow:

  1. A topic is created in a private staging category.
  2. That staging category is only visible to admins and a specific Weekly Challenge moderator group.
  3. The affected user is a global moderator and is also in that Weekly Challenge moderator group.
  4. The topic is scheduled to publish into our Image Critiques category.
  5. The destination category allows Members to Create, and the affected moderator is included in that access path.
  6. This workflow previously worked, but now fails with a 403.

This only appears to fail for the publish_to_category timer type. Other topic timer actions do not appear to fail in the same way.

Failed request:

POST /t/51041/timer

Request data:

time: 2026-05-31 07:52-04:00
status_type: publish_to_category
category_id: 87

Response:

{
“errors”: [“You are not permitted to view the requested resource.”],
“error_type”: “invalid_access”
}

Additional notes:

  • The user is a global moderator.
  • The user is TL4.
  • The user has access to the private staging category through the relevant group.
  • The destination category allows Create for Members.
  • Admins can set/change the same publishing date without issue.
  • We do not have any custom plugins or theme components modifying this behavior.
  • This started immediately after a core update.

Question:

Was there a recent authorization change around publish_to_category topic timers? Should a global moderator with access to the source category and create permission in the destination category still be able to schedule publishing, or is this now intended to be admin-only?