About this video

For some reason my FPS slows to a crawl (like 2 fps) but only when I am standing directly beside certain custom NPCs - a few examples include LIvia (as seen here), Remiel's Scrap summon (not Remiel herself), and Tabia.  A few others I've forgotten to take note of as well, I'm sure.

The best example is at around 1:20 or so, I forgot to turn on the FPS counter at first (it's on later), I go from 50-60 FPS to literally 2 FPS while standing next to Livia.

It's the strangest glitch I've seen in all my years of modding Skyrim.

Has anyone ever seen something similar?  This is so bizarre.

:/