After crafting the improvised weapon attachments (add use 2 burlap strips + 2 nettings) the improvised weapon attachments was create.
BUT: The result was: left of ingredients nettings -> 1x (that´s right) ; left of ingredients burlap strips -> 0x (BUG!)
After additional a burlap strip to the 0x strip the 0x strip was delele.
--> {F1202498}