IDK
Puzzle Rush Bug

Sometimes, rarely when I'm doing rated puzzles or rushes I come across a puzzle which requires some sort of castling. After doing it, the screen just freezes and remains unresponsive. On ios by the way. Is this just a bug?
Yes, it is a bug and I agree with you. But if you are having issues with the IOS app, please report them in the respective club! Also, if you'd like to know more, please visit support.chess.com
Sometimes, rarely when I'm doing rated puzzles or rushes I come across a puzzle which requires some sort of castling. After doing it, the screen just freezes and remains unresponsive. On ios by the way. Is this just a bug?