Hello!
The project is set to use Dynamic navmesh and that works. If an actor has “Can Ever Affect Navigation” turned ON on its Static Mesh component, that effectively affects navigation and cuts out a hole in the navmesh. If I move the actor around (both editor and PIE), the navmesh behaves as expected. So, all that is good.
If I then toggle the “Can Ever Affect Navigation” flag OFF, however, the previously created hole in the navmesh remains and NEVER goes. No amount of path rebuilding, navmesh volume deleting/replacing, original actors deleting helps, those holes stay there indefinitely; in the editor, the PIE, the stand-alone. The navmesh is only properly updated on editor restart. Running “RebuildNavigation” console command fixes the issue in runtime, but it will still stay in the editor.
It is as if when the flag is turned off, the navmesh stops considering that actor entirely, but forgets to patch itself up removing the previously made cut-outs.