LightmassImportanceVolume interfers with Navmesh path creating “ghost geometry/collisons” visible through Draw Path Colliding Geometry when checked in RecastNavmesh. Effectivly hacking up the navmesh path in random ways and allow navmesh to draw path onto thin air outside of any geometry or collision.
Moving the volume above the area and rebuilding path resolves the issue temporarly.
I am unable to reproduce this bug in a empty level.