Shadow Pieces setch

I can confirm that too, i can't replicate it in new worlds but every sketch i put in the potters wheel it turn into a pawn, when you hammer the wheel after you get a pawn figure sketch, losing the original sketch, i did lose 2 crab king sketches by doing it that 

Same issue. I put beefalo sketch and get pawn instead

If the sketch gave you the wrong figure, hammer the sculpting table, and rebuild it, then the sketch should give you the right figure.
Unfortunately, if you gave the sketch to a sculpting table(and it gave the wrong figure) that sketch cannot be re-obtained without console commands, all other sketches should still work fine.

Changed Status to Fixed