Hello,

I was playing in my Hardcore world and derped, because I pressed my "Strafe Right" key as I was in the menu, rather than my Inventory key, which is to the right of it. Then, it crashed. The crash report says:
The game crashed whilst ticking block entity
Error: java.lang.IllegalStateException: POI never registered at eu{x=215, y=66, z=-267}

It then crashes again with the same message. Load up the game again, and it functions as normal. Except apparently I can't access that barrel again...