Since the September update the female avatar's teeth show through the lips as the teeth appear to be to big for the mouth or perhaps got set off a bit. Changing the face shape doesn't appear to make any difference.
This is apparently not considered a bug as the return note from support said to post here as a request (eyes rolling a little :D).
You can see a photo of the problem here: https://tinyurl.com/ybrymqbp
This is the default avatar shape without any changes.