Exactly the same issue as the Black Hammer -
Once you have Hive Disruptor enabled, you can no longer get the Precision Mag Bonus (on Hive Majors), due to the extra damage to Hive Majors coming up as a separate value on the body in white (which your bad programming then registers as a body-shot) thus ruining the precision chain.
Do you guys ever test anything? I mean like ever?
Clearly this was going to happen as it does on Black Hammer where you disabled Hive Disruptor, but you didn't think to test and pre-disable it on Word of Crota which relies on the same mechanic and would obviously fall victim to the same bug?!
BTW please don't disable Hive Disruptor on it, ~I Would rather have that than the Precision Chain, but fix both guns asap.
(Just add the extra damage to the total damage and you should be fine - as obviously making it yellow (aka a precision shot) would mess up the chain too.
-
I also have noticed that on top of the fact that that perk is not very good to start with, it doesn't even work. Fatebringer is still better.