[0.91.9]Builder getting stuck after finishing wall

[Stealthkibbler]

Sometimes when my builder is done finishing a wall he just completely freezes on spot and is unable to move at all, picking him up and dropping him seems to resolve the problem but almost everytime he finishes a wall this happens. The walls were built on sloped ground near Stack but most of it was even land.

[Drag00ne]

I can confirm this in 0.91.12 too and my base is in the green land between Blister Hill and Bad Teeth. Most of the terrain is flat there. I did not tried to pick up the builder but deleted some parts of the wall. On rebuild it not always happen.