What is the taliban grief with Pakistan?
It's one of those "It's complicated" relationships.
The Taliban is not a tribe, it is a cult, for want of a better word. The vast majority of the Taliban are Pashtun though, occupying the border between Pakistan and Afghanistan. They don't bother with the concept of borders at all, moving back and forth freely in their day to day lives. They are also wickedly inventive, born mechanics (watching someone sitting cross legged on the ground turning out a AK-47 copy out of scrap and basic tools is pretty humbling), born warriors, and crack shots, so a lot of none Taliban Pashtun wind up in the Pakistani Army, usually fighting India over Kashmir province.
They also despise the lowlanders who make up the bulk of the armed forces and all of it's command staff. A common complaint by the tribe is they get sent in to do the dirty work and be slaughtered. So there is tribal resentment. Rather a lot of it, and they know how to hold grudges.
The Taliban itself is not exactly fond of the Pakistani government's collusion with the USA, even though much of the time the government turns a blind eye to border activity that does not threaten their own security. This action was probably a tap on the nose to the government, equal parts grudge, tribal loyalty and publicity.
Like I said - it's complicated.