Ok so for some reason I cannot equip the part 4 on the rifle, don't know why. I've done all the quests and I have the triumphs to prove it. Currently I have up Hunters trace III on it. I think this bug happened because I did the quests once u had acceses to all 4 and kinda did em in a wacky order. I had done 1 2 4 and forgot to grab robot for 3. 1 2 4 then combined into one final quest, Then i went back and got 3. Then went to gunsmith with 2 different Quests completing all of them at once. But yet i cannot equip the Fourth Hunters Trace. Ive done everything possible to do, even talked to a very friendly robo dog. Please Help