Unfortunately, I don’t know what they are or how to correctly reproduce the issue, but I have some avatars uploaded that do have this issue:

In the quick menu, these avatars just make the majority of the menu blue whenever they’re being previewed. I don’t know what it looks like when others use it.

I also attached a picture of my friend’s avatar, since it’s not public, but has this issue and shows what it looks like.

Maybe it’s GoGoLoco or one of the avatar’s bounding boxes?