Thrall's Falling Through Player-Built Structures

Game mode: Private RP-PvP (no mods)
Problem: Bug with thralls and player-built structures

I was using a bearer thrall to haul stone back into an office that I had constructed in a structure that was raised off the ground.

After attempting to follow me onto the player-built structure, the thrall NPC then fell through the foundation pieces, floor pieces, etc., straight to the ground, where he died and his legs fell off. (lol)

Is this a known glitch? Anything more I can do to help report the bug? Thanks!