Lately I have that if the end boss is killed and I move away to get some gems or weapons the end zone disapears and doesnt come back. I then have to move back a pretty long while, then come back and it comes back slowly after I stand on or very near the spot where it is supposed to be.

Even though I think it is because of my high ping I still post it, in case anyone else has it too and it has another reason.

In the end it does always come back though, so not a really big issue.