Like it's says in the title, I can't get the blueprint for those infected knives.
I've played through most of the side quest in DL1 in my first play through but never got the blueprint.
Later, I checked on Wiki that I can obtain them by buying at Craftmaster at the Fisheye, but I checked and all it was is just materials left(I bought every upgrade). And no Infected Blades.
Please, If anyone knows What exact mission I must complete to get the blueprint or some tutorial, tell me. Techland, please fix this, such blueprint bugs was in DL1 and now here.