Carpenter quest becomes unwinnable if Yrrigs transforms into a WMoPC
If the mad carpenter transforms into a writhing mass of primal chaos, Rynt's quest cannot be finished.
Problem
If Yrrigs transforms into a WMoPC, the game no longer recognizes him as the mad carpenter and Rynt's quest becomes unwinnable.
How to reproduce it
Take Rynt's quest. Find the mad carpenter on VD: 7 and lure him to a corruption trap many times. Eventually, he will transform into "Yrrigs, the writhing mass of primal chaos" (at least he kept his name). At this point, neither killing his new form or taking it to the healer will fulfill the quest - if you go to Rynt, he will keep on asking you to end the carpenter's suffering.
Notes
This could probably be fixed by making the game act as if Yrrigs died/had been killed by the PC when he accumulates so much corruption.