I’m running bc1cecd. I found a survivor who attacked me wielding a monomolecular blade. After killing them I picked it up and wielded it (I didn’t know it came from a CBM). From then on the game wouldn’t let me drop, trow, or unwield it, or pick anything up while holding it. It’s kind of a death sentence by starvation. 
Try debugging it off? I don’t know if its possible.
okay, I was able to wish for the monomolecular blade CBM and successfully install it. That let me retract it. It’d be nice if an NPC with the blade wouldn’t drop it when they died. Maybe the CBM could be obtained after butchering their corpse, like with shocker zombies?