If you’re an admin, you can try to manually use rebuild HTML from this menu within under the post to see if that updates the avatar:
If that works… then rebaking is working as expected, but the automatic process either hasn’t made it to all the posts yet, or has failed for some reason.
I didn’t think the quotes got automatically rebaked due to an avatar change anymore? Some of mine pre-picture still show the ‘J’ (though will update if I edit or rebuild html): eg
The plugin is active but not in the bug category. After a bug was fixed the topic is closed. If no fix is needed the topic is moved to a different category.
Manually rebuilding fixes the problem for one post. But I would not call that a solution. If there are many posts where the profie picture was not changed, this can be time-consuming.
Also it looks worse if there was a profile picture before, because that is deleted after some time.