Saving and quitting, coming back and immediately dying- offline mode

So this has happen to me a few times- where I save in a safe location. Nowhere near enemies, lava, or underwater. Nothing should be harming my character while I’m logging on or off and this is in offline mode, so nobody else is in the world except my character.  Then when I come back to my save it is on the respawn screen saying I died. The last time this happened I had saved and quit and immediately relogged back onto the file and was dead. It’s the game kept playing without me being on