I was walking East of riften when I came across 3 dead imperials guards, all of them stripped of armour and looted of weapons, i carried on some more to find two dark elves and a Orc in imperial guard armour and plotting something.

Ah yes - look out ...

The weirdest thing I've seen in the vanilla game was a dead horse attached to a burned wagon way up in the mountains. The horse was 80% under the ground so only a little was showing - quite strange and disturbing.

The weirdest thing I've seen was a mammoth riding on the back of a flying dragon, who dropped the mammoth off on top of a mountain.

Jarl Balgruuf sitting in that jarl-slouching posture...in midair, a good twenty feet away from his chair. Everybody else is standing around, conversing with his empty chair.

I was in markarth today, started the Sanguine quest, when I left the temple of Dibella I just saw a lone markarth guard rise up into the air and fly away. I guess his people needed him more then the reach did.

Sometimes, when I fast travel to Dragons Reach, a couple of guards on both sides of the walkway drop from a short height and go splash into the water. Other times the guards are in their normal spots but I just hear a splash.
If I've arrived in a cell, via fast travel or walking/riding, an npc will be flung across the sky as if shot from a cannon.
I have v-sync on, but quite a few script - heavy mods so I just expect strange things to happen now and then

the splash is probably coming from it loading the Skeleton located under the dragonsreach bridge

The headless horseman Ghost and a Wolf Ghost..