In my personal experience, NavMesh only works in the persistent level. It does NOT work in sub levels, streaming level or level instances. I’ve never been able to get that to work. You can try putting navmesh, volumes, whatever, they all get ignored unless they’re in the persistent level.
If someone has a solution to this, I’d like to hear it because I’ve tried everything.
BTW, for level streaming, just set your navmesh volume to be big enough and set the nav mesh to be dynamic and that should work. But all navigation has to be in the persistent level.