And, you are using the built in Pathfinding behavior? Finding a path to where the enemy should move to. Something like, "Event Condition(s)" > "Pathfinding: Find path to (Object.X, Object.Y"). Then "On Pathfinding path found" > "Pathfinding: Move along path"?
Also, making sure that the object it is trying to move through is a "Solid"? Also, double check the bounding/collision box, of the object it is colliding with?