[Trexmaster]

Both issues refer to a bow that was originally a gun (a mutated Yin/Yang, i.e. originally a gun, mutated into a bow.).

I'm unsure if it was an intentional change with Headshot, but a few patches ago it started having multi-round guns fire all of their rounds when used as opposed to only one shot like it had in prior patches. It wasn't that much of an issue, but now it causes former-gun weapons to fire all their rounds anyway despite being mutated into a Bow (which normally causes multi-round guns to only attack once).

As for the other issue, it's just when you use a normal, non-mutated handgun with a mutated handgun that would otherwise only attack once whilst using Akimbo.
I.E. A normal Yin and a mutated Yang.
1. Double Dao for +2 rounds to each (4/4)
2. Fire with the Yin, causing the Yin to shoot 4 times, then the Yang to shoot twice, despite being a Bow.
3. Fire with the Yang, causing the Yang to attack once without any additional attacks from the Yin due to the Yang being a Bow, and not a Gun.