This happened to me again today. Two days in a row with two different saves, only playing single player. Each time this happened I would logout and then login later and would have to re-spawn just to play that save. I would re-spawn with zero items, on the spawn island, and "where my body" should have been there was nothing. No items, no tombstone, nothing. Also I was in my base protected from animals or any kind of outside danger when logging out...