The times it has been happening to me are on a map with only one character ever on the map, and that character has never been to the End. There appear to be multiple ways for this to happen.
This happened to me again this morning making this 3 days in a row. I’m using on Minecraft PE on Windows 10. The exact version installed is 1.8.24.0.
I can be contacted to provide an export of the world if needed by support.
This issue has hit me twice in two days. I would rather not wait until 1.9 in Spring of 2019 for a fix and would much rather have a 1.8 dot release and more rapid fix.
This bug really sucks the fun out of the game.
Unfortunately, I’ve had it happen several times so far, even when I am using a bed. Placing water at the world spawn point has helped.
Despite using a bed, I am regularly spawned in a different heights form where my bed is, and sometimes back at the world spawn point. Perhaps something is wrong with setting spawn points in general in 1.8.