Inivisible Attacks of Opportunity?

[Vilrandir]

This question arised in my last game of Pathfinder. An invisible creature abandons a threatened square. Does he cause an attack of opportunity ? Can someone take it? We ruled that a perception check would be made for the PCs to notice the creature abandoning the square, therefore allowing the AoO for those who succeeded. Does this sound right?

[Svipdag]

Core rules p197 state:

You can’t execute an attack of opportunity against an
opponent with total concealment, even if you know what
square or squares the opponent occupies.

So unless you could see the invisible creature, thus negating its full concealment there is no attack of opportunity.

[Vilrandir]

Thank you.