Yesterday I logged in and was Unconscious. There is no way I was killed by a zombie as I was very well away where any of them are, and no players either. Also, it showed that I was thirsty and starving. Not sure if this is the same thing as OP as I don't necessarily log in dead, but it happened to me 3 times yesterday and happened to one of my friends and a couple new spawns I talked to. It seems like if you get stuck at "please wait," then your character is being deleted or killed... If I hit escape on the "please wait" screen, it shows a freeze frame of me being in first person and under water...