I experience this a lot, too- from what I understand, it happens when you go from releasing something with that many idols to releasing something with only a few. It'll put white boxes where everyone else was in the last single/show. Happens all the time when I put out solo songs (I know that's probably bad strategy, but don't judge me, I've got a storyline going and I want to keep it up sdlfkjsdlfj). Doesn't seem to affect anything other than the visuals tho