Next time this occurs on your site, please PM me so I can look at the entry before you approve it. It is easier to guess the reason before it gets approved.
Note that even though your permissions allow this content without moderator approval and you have nothing in the spam-trigger log, it is still possible to get already existing content to need approval in the following ways:
- A moderator has decided the content needs review, and sends it back to the approval queue.
- A rollback or a purge of the current edit occurs, and the only remaining edits were soft-deleted or rejected. A moderator needs to review the content now.
Outside of permissions or a spam detection, any other reason for content appearing in the queue could be a bug; however, the reason can vary widely depending on the content.
Confirmed that there is currently no integration with XF2's moderator log, which makes this harder to diagnose.