I am currently writing a plugin that allows players to hide chests by covering all sides with solid blocks. Everything works just fine, it hides and unhides just fine, no problems. It saves and loads, as well as runs a thread to send the hide packet to all once a minute. I personally do not crash, as well as most of the players who test for me. Some players do crash though, and this happens every time the server sends them the block change packet. I have tried everything I could, but still I cannot figure out what's wrong. Any suggestions?