I think you may be right.
- Reset security permissions by removing all groups (No groups have been granted access; this category will only be visible to staff.)
- Added in ‘everyone’ with all permissions (checked test user - working as expected
) - Unticked ‘create’, and refreshed (screen displays a reversion to all being ticked)
- Check test user, and they can no longer create a topic in that category, despite the security screen showing they can
And a similar thing when adding a second group alongside ‘everyone’. The ‘everyone’ group disappears from the display, but the permissions seem to be enacted.
It seems it’s also restricted to the ‘everyone’ group. Others I can add and amend permissions for, and they seem to stick just fine.