Enemy kills you. It / Loot becomes invisible

Put the summary of the bug you're having here

What I expected to happen was...:
I expected to return to the spot where I was killed and be able to see my dropped loot and maybe the mob that killed me.

What actually happened was...:
I returned to the spot and the mob could not be seen, but I was attacked and killed again by an invisible mob. (This has also happened with skeletons). Sometimes my dropped inventory was also invisible, but could be picked up by walking around the spot where I was killed.

Steps to Reproduce:
1. Get killed by a mob
2. Return to the spot without leaving the game
3. ...