Game Mechanics: Fletching bug?

[DDraven]

I'm not sure if anybody is aware, but there may be a fletching bug. When i put a hickory bow staff and a linen or silk string in the kit, the stats of the finished bow are supposed to be different depending on which type of string you use, but they aren't. I still get the dmg 10 delay 50 bow even if i use silk, which is supposed to give a dmg 8 delay 42 bow.