Riften Jail (RiftenJail01): partition wall disappears from the stair room
USSEP disables REFR 000A8E93 (RifRmSmPartitionBase01) as a duplicate of 000F9AE8. It isn’t one: both copies sit at the same spot, but each is bound to a different room via XMBR (0A8E93 → room 0A8D3C, 0F9AE8 → room 0EC450). With 0A8E93 disabled, the wall vanishes from the stair room whenever portal 0A8D43 is out of view (first and third person). Restoring 0A8E93 to vanilla fixes it. Tested with USSEP 4.3.9c.
Report from a user on the nexusmods ussep page