Inside the Drunken Huntsman there is an Iron Arrow [000C7AE2] that always appears on the floor just before Elrindir's counter. There is also an Iron Dagger [000C7AE2] that inconsistently shifts placement upon different playthroughs, sometimes appearing on the floor. Toggling collision (TCL) prior to entering the Drunken Huntsman shows me that the Iron Arrow starts placed on the floor and the Iron Dagger on the counter, but re-enabling collision will ocasionally cause the Iron Dagger to clip into the counter and 'pop' out, with the possibility of landing on the floor. The Iron Arrow also does not have any ownership set which likely affects its ability to be purchased, but I'm unsure if that qualifies as an issue since only the items on the counter have set ownership and the arrow may not necessarily be meant to be on the counter (it most likely is though).
Here is a short
video clip to demonstrate the issue.
I also included an unrelated, very minor issue that occurs in Vanilla and with USSEP in the clip. There is a slight gap between the floor mesh and the counter mesh through which the player can see the skybox.