those weird engravings that get left in limbo after you remove the construction they where carved into causes an indefinite freeze if ssense looks at it. The workaround is to build a wall over the engraving, carve it into a fortification, then remove that. Engraving gone, ssense happy.
from: https://steamcommunity.com/app/2346660/discussions/0/4032475099155804172/?tscn=1703217477