This seems to be an issue with the Wraith, from what I can tell. It has been rather common for me on Xbox One. The Wraith will melee a downed player to death, and their corpse will clip through the floor or be sent flying out of bounds and become un-revivifyable. I would love to see a fix for this, as Lazarus can’t work well without bodies.
p.s. There is also a weird graphical glitch with Lazarus’s flashlight showing shadows through floors of objects. Not game-breaking, but a bit ugly.