Dissapearing bedrock

My game stopped responding. i try to kill mushrooms by command and i forgot id. i run google chrome and my game stopped responding. i killed it and run it. i go to the end and fly to the portal to test spawn chunks. portal is bad look, first I thought its unloaded chunks, but no. two chunks generated endstone and air in portal and destroy half of portal. destroy bedrock, torches, and portal.