Is it possible change NavMesh so enemies can fall down holes.

I was wondering if it was possible to change NavMesh so enemies can still fall down holes and into pits

Not tested but if you had a plane collider that does not collide with characters but is set tagged for navMesh generation, the NavMesh would not be able to tell if there is a pit there, and the characters would fall in since the plane collider does not collide with their character controller.