I know this has been brought up before:

I'm having some severe problems with losing an NPC body after they're killed. It only recently started happening in game, but it's quite frequent.

I killed some bandits on a bridge above the road (with the aid of an atronach and my NPC). After they fell, went up the stairs to look for them, neither body was to be found. Figured if perhaps they sank, maybe they were on the road below where they were perched. Again, no sign of them. I didn't bother restarting, but have noticed this more and more and it's getting fairly aggravating. I have yet to witness them sink away since the last few times I've still been in combat and couldn't really pay attention to the kill. It's been happening frequently with the humanoid characters vs. monsters. You can walk the area they died, no trace of them or their items.

I do hope that it's been brought up enough to be considered for a future patch.

I cannot say I have seen this myself. The closest I have seen to this is when you kill an NPC who is sitting or sleeping. Once killed they will sink below the item they were using, like the NPC will transport below the bed you just killed him on. I wonder if it may be related.

I have had this happen a bunch of times. One thing I noticed though, if you stare at the ground around the area where they dropped, it will cue the search body function, and can still loot them when selected, there is just no body there. Weird.

Ah I have had this issue a few times, especially the 'bed' one. In fact, every time I kill a sleeping person...(quite frequent...not many people left in Whiterun) they end up under the bed -.-; I always think it's because the character is secretly hiding the evidence O_O; Or when they sink slightly into the ground that my character has buried them. Although encasing them in cement and turning them into a land mark feature when they sink slightly into a large rock is kinda far fetched I guess >_>

this happens rarely for me, most of the time when they do fall into the floor they come back up, but i have had them disappear into the floor a few times, try grabing them and trying to pull the to the suface.

Like crunch and Ravenshade stated I have noticed the bed thing too. I also killed a few bandits next to a wood wall with firing an arrow at them and they end up dead behind the wood wall and the cave wall. All I had to do was go to the side the move my cursor over where the bandit is to get too the loot. Now once I killed a guy and he disapeard, but I moved my cursor over the last place the guy was on the ground and I got a lock on the invisable body on the ground near where he last was.

Any time i kill someone on stairs they disapear. Its about 50-50 if i can loot them afterwards.

i get this alot... seeing as i am a silent/sneaky killer...

-npcs falling thru/under the bed, eg. the gourmet getting stuck inside or under the bed preventing me from moving the body to get the bonus also ive had sleeping ppl i paralyse jerk & get stuch halfway in the bed
-npcs fallin inside the ground or wall etc... i had olaf fall completely in the ground no way to loot...if i needed an item off the body i would have been screwed
-npcs getting stuck inside the object or chair they are sitting on

this is very annoying...

Yeah, stairs tend to trigger this too. I just never get to loot the body. Will search the general area where they disappeared and nothing happens So I just move on and and hope random bad guy doesn't have that ONE thing I might really like. I've only killed one or two people in their sleep and their body has remained on the bed for the most part. Just the randoms elsewhere in the world are misbehaving right now.

This is called "clipping". Mainly it's just bad code/physics.

I had to switch to a bow for many kills. Hell, I was sending npcs thru walls, floors, beds. The physics when hitting hard is really bad coding.

I did notice once my one arm skill started to go above 100ish, the clipping got really bad.

I too noticed the bed (bug) mostly through the DB questline but then noticed it was also happening during battles and after a scrap bodies were missing, I'd kill 5 but only find 3 or kill 6 but only find 4 afterwards.

A little clipping I can handle, but to the extent of losing the 'reward' is no good. Wonder if this is something that can be fixed.

I would imagine it will be cleaned up at some point

I sure hope so. I know this isn't a first time report of this issue. So hopefully that'll help.

I haven't seen this problem exactly but something pretty close. My game world is often littered with floating weapons. After killing enemies I would often not bother picking up the lousy weapons they carried. Unfortunately after coming back through the same area days later the weapons are often just floating in the air. I can't click on them and pick them up. Sometimes if I keep trying to run into the floating weapons, they will fall to the ground.

For this reason I feel like every enemy I kill I need to collect the weapons. It just annoys me when I'm trying to enjoy the nice visuals of Skyrim only to have it ruined by a bunch of floating swords, axes and bows.