@littlefox saidAre you moving the king two squares towards the rook?
when I attempt to castle, only the King gets moved correctly, the rook erroneously stays in place. Not sure what will happen if I submit that move, haven't tried that yet. Don't want to trap my rook like that. This appears to be a recently developed problem.
If you only move it one square, that's not castling, it's just a king move.