The entire underside of the trishape WHMarketSide02:3 is missing. I have attached a fixed mesh, where I also reworked the canopy using double single-sided faces instead of a double-sided texture. The latter should ideally be fixed on WHMarketStall01.nif too, but I leave it to you to decide whether that is important enough to include in USSEP.

Attached Files:
whmarketstall02.nif