When i pushed the end chest with a piston it stopped my game, didn't crash but minecraft became completely unplayable. Ended up force closing it. This has happened to me twice so it wasn't a one off bug. Also when re-logging the end chest was pushed. Would it be possible to leave it with the ability to be pushed? Thanks!

Ender chests are not meant to be moved with pistons, This is an issue because of another mod allowing this to happen.