Can't change a BB/BT boolean from a pawn BP

I’m trying to swap from a simple roam AI to a follow player character AI on end overlap. Basically trying to build a train, so to speak, of pawns following behind the player character. I have the mounting and possessing by the player controller working, but when I mount a different npc the logic returns to the roam instead of the follow.

I’ve trouble shot everything and I basically I’m sure I’m not correctly passing the boolean change from the pawn, to the controller, to the blackboard. Even event tick doesn’t seem to work and I thought, at least for testing purposes, that it would.

Any help would be greatly appreciated!