AI image-generative models have a reputation for illegal content. AI image users have a reputation for caring less about social rules for production over time.
My guess is there’s a flag on your game or account, along with others, for the moderation team to watch out for this downslide. When your update surfaces in the moderation queue, a peek at the page shows the characters still look like adults who don’t closely resemble real celebrities abusing moral rights, and it’s approved for indexing.
Hiding the images might worsen the delay. An obvious drop in quality could do the same. Changing out the images… eh? I can believe that matters.
In my opinion, previews should match downloads, so if they need to change, they need to change.