I was here, now I'm there.

At my base AFKing in a closed safe place. Coordinates at -48, 69, -299. I put down the game for 5 minutes and come back. My character is now in a blue void, can see the sun rise and fall. Can not move and are not falling. Coordinates now at -2147483648, 69, -2147483648. Save and quitting/logging back in, fixed the problem. But it's still a thing that happened.