Two different issues in this thread or perhaps one issue manifesting itself in two different ways.

AnimatronicLouReed was killed. No map marker showing the location of the corpse appeared on the map. There was a corpse in the world at the place of death.

Minagho was also killed. A map marker did appear on the map. There was no corpse in the world at the place of death.

I have had experiences similar to AnamatronicLouReed. While I don't recall ever dying and having no map marker, I recall several occasions where the map marker disappeared from the map before I got to the corpse. I got into the habit of opening the map immediately after death and placing an additional marker on top of the game-generated one.

I cannot recall ever dying without leaving a corpse, as happened to Minagho. Minagho plays on a server open to other players. The paranoid in me suggests another viking looted Minagho's corpse.