Thralls on following, falling through building pieces

Game mode: [Online]
Problem: [Bug]
Region: [North Ameriva]

Thralls on following, falling through Tier 1 Ceilings, Foundations, Stairs. T2 Ceilings and Foundations, Drawbridges. This does not happen every time, but I have managed to reproduce it three times. It is not always fatal depending on the height. Last night I had a T1 Stygian Bearer fall through the drawbridge after I crossed that was 4 levels high and it killed her. It appears the issue is with buildings pieces, not world terrain.

Steps on how to reproduce issue:

  1. Put thrall on following.
  2. Run up/down stairs, drawbridges, floor, ceiling.
  3. Watch thrall disappear/fall to death.