They've allegedly sold weapons to the BLA via the black market.The black hawk belongs to the US Army Alpha company, read the text below the picture. The taliban don't have their hands on it.
In fact, the taliban tend to destroy any helicopters they see, because they know they can't operate them, and don't want them going back into government hands.
[Edit] frankly, the taliban need to be watched like hawks. Pakistan needs to make sure that these systems don't make their way to TTP and BLA hands.
Fencing and surveillance needs to be of the utmost priority.