So, I walked into the town across the dragon bridge for the first time yesterday when I noticed a horse and rider zipping forward at lightning speed into the side of a building. I tried to walk up to it but it appears that my actions impacted its movements as it immediately began to fly into the air and zip around in the air odd jerky motions. If I stopped moving, it would just float steadily away until it zipped out of my view and would then show up a moment later galloping towards me like nothing had just happen. If I moved, it would all happen again, if I did not move and it got a certain distance away from me it would start odd actions.

It occurs to me that I haven't seen many/any NPCs on horses. Is there anything in particular that causes this (I only use the Unofficial Skyrim Patch, zero other mods)? I've seen videos where killed animals fly off in the disance and a few others, but not NPCs on horses. But this doesn't surprise me. I've just not run into almost any glitches in the game. Less than 3.