Hello. I noticed after installing the update for vanish, if you are in vanish the bases still render in and out and partially disappear. With vanish off they seem to be alright. However, when I went to paste a 2nd base, I pasted it too high so I did /undo and it deleted the first base, not the 2nd. When I went to manually delete the pasted base, there were pieces still floating in the air. 

Disappearing sounds like a Vanish issue if it happens only with vanish on. I will take a look at stuff that deletes entities.