Check location on navmesh for obstacle

Hello! I am working on a game where AI is allowed to walk in certain areas, but is discouraged from doing so (picture something like hot coals they can walk over to get to their target but only if they HAVE to).

I implemented this behaviour using NavModifierVolumes with the AreaClass set to NavArea_Obstacle.

My issue now is that sometimes I want the bots to freely roam about. I set up a simple roaming task using GetRandomReachablePointInRadius – the problem though is that now they will walk onto the hot coals when they don’t need to. I want them to ONLY roam on the open navmesh areas (NavArea_Default).

Does anyone have any ideas how to accomplish this?