How did you calculate the room bounds? I tried this, but some rooms are not inside the navmesh bounds.
Update: I found it.
UPROPERTY()
ANavMeshBoundsVolume* DungeonNavMeshVolume;
---------------------------------------------------------
UBrushComponent* BrushComp = DungeonNavMeshVolume->GetBrushComponent()
FBoxSphereBounds NewBounds;
NewBounds.BoxExtent = Extent;
NewBounds.Origin = Location;
NewBounds.SphereRadius = Extent.Size();
BrushComp->Bounds = NewBounds;