Whether you use GML or DnD is irrelevant. Posting DnD counts as posting code.
Are any of the objects involved here solid? If so, make them not be solid. Otherwise, you're literally instructing the game engine to reset the positions of instances that are involved in a Collision event with solid instances every step until they are no longer colliding. That will essentially halt any movement once they are colliding until they stop moving into each other.