Well, in fact the exact problem was, I wanted the NPC to stop running towards me if there is no valid path, the AI always ran the NPC to the closest point, I found the solution to my problem in the Node “MoveToLocationOrActor” with the property “AcceptPartialPath” set to false.
But there is something, checking the path validity with IsValid always yielded true, I’m afraid that I’ll stuck in the same situtation again