That sounds like a classic “hot pursuit” situation rather than an invasion of Pakistan.

Hot pursuit over borders is always problematic - most countries would feel at least irritated if it happened to them (consider how many in the US would feel if the Mexican air force dropped bombs on the US trying to get fleeing bandits).

I'm pretty sure the forces were acting in good faith. The question is whether or not it was cleared at a higher level before hand, and proper notification was given. If it was, this is a non-issue. If it wasn't, then its a problem.

In a statement issued from Afghanistan, the coalition said it had retaliated after its forces came under small arms and rocket-propelled grenade fire about 200 yards inside Afghanistan’s eastern Kunar province during an operation that had been “previously coordinated” with Pakistan.

That sounds like a classic “hot pursuit” situation rather than an invasion of Pakistan.

I think it's a bit early to draw any conclusions about this. Somebody shot at somebody. Somebody else shot back. Somebody was killed. We can probably agree on that. Beyond that we'll probably need some independent confirmation to decide what happened.