Flickering bugs in general are caused by 4 possible reasons.:
- Models should not be spawned under terrain. At least a small part should be above it (caves and so on).
- M2s can't be spawned in WMO interiors via Noggit. There's no way around.
- Floors of WMO interiors must be either in hole in terrain, or above the terrain, and enough space between floor and ground is needed. If floor is too near to terrain or actually under it, flickering is here.
- WMOs must not be spawned in each other, their interiors must not even overlap.
I'd say your WMO is most likely duplicated.
