Limit Reviews feature breaking after approval/unapproval

I have the Limit Reviews option in Settings > Submissions set to limit by username, which initially works, but as soon as I approve or unapprove a review, the same user is able to submit another review.

I think I’ve narrowed the issue down to the author_id field, which is initially set to the correct user ID, but becomes 0 after I approve or unapprove the review.