AI agents destination confusion

My AI agents think that they reach their destination that is actually above their head, but in the same spot from the top view.
The Nav Map allows them access to both spots. Question: what is the role of the radius of acceptance in the AIMoveTo?
How can I make AI agents run upstairs to the correct target point?

More precisely, they go to the target point, but if on the way they bump at each other or jump and bump at the other static meshes they still run to the target point, except under the slide. They won’t go back up to the stairs.