Active slaves can not walk on the Foundation and climb to the second floor

Platform: PC
Game mode: Private Testlive
Version: 94750/17645
Problem: Bug

I decided to take the slave war. The first thing that caught my eye is that he fell to the knee in the texture of the Foundation of the house. I didn’t think much of it and went to the second floor by arrows. Before that, I saw that one of the slaves could not stand on the second floor, falling to the first.This time, going down, I saw that my slave was dead. He died of a fall, apparently. That was very stupid, hah.

Repro steps:
1.Take a slave who can move on his own
2.Climb to the second floor by stairs
3.Watch as he teleports to you and falls down

This happens to me too. They seem to fall into the foundation below and die.