Lets say I have a character with Improved Targeting: Ignores Blocking terrain. When a ranged combat attack resolves, any blocking terrain along its line of fire to the target is destroyed.

This character makes a ranged attack through blocking at someone with Probability Control. Can that figure force my shooter to reroll?

To ask another way, when is the terrain destroyed as compared to when Probability Control is triggered?

Probability Control is used during the attack, so the attack hasn't resolved yet. Therefore, the terrain would still be there.

So the terrain is gone after the attack and the one being shot would not be able to prob the attack? Vicious.