Digging to the bottom layer can get a character stuck

I dug down to the bottom assuming there was some kind of bedrock at the bottom of the world. There was not. I controlled my ruler to speed up the last few layers, and they ended up stuck there on layer -15, and I can't build any stairs on that layer.

So yeah there isn't a floor below that layer but they can't fall so they just kinda hover/float around. Can't jump(not that that would get me to the hole anyway). Also in that state I can just go through the undug terrain around and move around anywhere horizontally.