Help! Weird hover bot behavior!

OK, so I have multiple rooms in my microgame FPS. The bots in some rooms move towards me as they should but in other rooms, they move towards me at a snail's pace taking 30 seconds to get close enough to fire at me. But if I go to back to the room where the bots are working OK, leaving the slow bots behind, the slow bots suddenly come after me at a normal pace and attack me. In other places, one bot will come at me normally but the one next to it, a copy of the working one, won't. but if I move the one that doesn't work into the area where the others work, it starts working properly. I have patrol points for some and they patrol just fine, but then can't come at me normally when they see me. I have baked the navigation. I am at wits end to figure this out.

 

Sometimes a debug video can be useful when the behavior is complex.
I try to disable the component one by one and play to find the component that triggers the issue.

 

Video too big to upload.

https://www.dropbox.com/s/efdqmdqjdh37dln/movie_001.mp4?dl=0

 

More testing. Sometimes the bots can come at me normally, but other times not. Sometimes they won't move towards me normally, then suddenly return to normal behavior and come at me at a normal pace. Some new bots act normally, other new bots don't. It doesn't seem to be area related as this behavior occurs in multiple places. I started a new level and they suddenly started doing this on that level when they were behaving normally at the start. I'm getting very frustrated since I'm a beginner and have no clue how to track this bug down.

 

OK, it has something to do with conflicting nav grids. I put a probuild structure under my floors and for some reason that messed up the navigation on the bots. I removed the floors and the bots behave normally over that part of the place. Not sure how to deal with two overlapping nav grids since I can't remove all the floors.