Just installed in OpenMW. First vendor NPC (Ahtimbar) in Old Ebonheart is rapidly bouncing up and down, jittering if you will. They don't move around, they are standing behind a stall and I don't see this problem with moving NPCs. I could swear I saw mention of this somewhere and a fix, but it escapes me atm. I have an upscaled texture pack installed, and a few other minor mods. Will upload a mod list shortly.
Edited for clarity.