Hole in the Navmesh

During my playtest in the game that I’m working on, I found some kind of bug that I have no clue how it came from. Basically, after I play for a few minutes, holes in the navmesh start appearing—and to that mostly only where my player was during the game. This is VERY BAD because my game is about players fighting bots, and dysfunctional navmesh is going to ruin the bots. Here’s a picture of what’s going on.

All the remaining alive bots are on the edge of the navmesh because they can’t navigate to my position while I’m inside the hole.

Not worked with pathfinding in a while, so I’m not sure how useful my reply will be but here goes. Is it something to do with the cost of some area that is too high for the bots to want to take? IIRC the navmesh should still generate there/the bots should take that route if other options are unavailable. Can the bots climb the stairs/is there another way to get into the enclosed area that is not shown - perhaps there is no mesh because the bots can’t get in there?

Cost is undefined in the parameters. The bots can climb the stairs, if you look closely into the photo, you can see dead bots within the navmesh ‘deadzone’—they got there through the stairs and I killed them. However, as I said, after a while a hole in the navmesh appeared. I unfortunately am unable to verify how that hole exactly creates itself, as I can’t oversee the client and the server at the same time during playtests. The issue is still there.

navmesh

Check for any humanoids that aren’t in models, this caused me a headache a while back where I ungrouped a model with a humanoid in it, causing the whole nav mesh to disappear.

I checked Humanoids, I couldn’t find any that were outside their models. What I found, however, is that when I fire a gun, the navmesh disappears in the area that I am in.