Today alone, I have had 4 legendary mobs that I killed just despawn.
https://i.imgur.com/FeLeX8G.jpg
This is an example. corpse was loot able as it was falling and then poof, now its a prop in the world.
This is all within 15 minutes.
I realize now I have several others do the same, but this really caught my attention since they were legendary.
This is on PC.
Thanks for flagging, just confirming that we've passed this one on to the team.