Can also confirm the freeze when climbing over a fence. Though.. the heavy fps drop in my save doesn't seem to be fence related, as there's a fence directly to my west, and going near it doesn't cause the fps drop. The reproducible fps drop only happens strictly when moving slightly north (top right).
EDIT: Nevermind, it IS from the fence. Moving north put's me on the other side of the fence to my west, which turns on the see-through thing, and causes the insane fps drop.