I made a simple maze to test how my chase AI would work inside of it. When I created the nav mesh I ran into all kinds of problems where my character would try to path find to a unreachable space. I was stumped for a while until I used the wireframe view to see if anything was off and I found this. A bunch of small squares that are inside/under the walls of the maze. (Photo 1) How is that even possible? All I did was use a default UE cube mesh and scale it a little bit for the walls. I have tried changing Min Region Size to fix the issue, but that only got rid of some of squares. (Photo 2) Any help would be greatly appreciated as I spent 2 hours trying to debug my behavior tree because I though that was causing it. Thanks
Create your own cube (there is plugin to make meshes).
Or copy that default cube (if it is in Engine folder, and not in project files) and see its collision in mesh editor (double click in in content browser or right click and open).
So first is to look at collision, and since it is cube, you can remove old collision and add box collision there.