I get this message when I leave any world at any point and still don't know what to do about it.

To recreate this bug you must simply:

1. Open up any world in minecraft (on Xbox exclusively?)

2. Play it for as long as you want it doesn't really matter how long it's played

3. Leave and receive a message saying either (World upload failed) or (Local save successful)

For the world upload failed message I get a cancel or retry request I press retry and no matter how many times it just never syncs. This basically means that because my world didn't save to the cloud any local save data I have on my xbox will be deleted upon uninstalling minecraft or trying to transfer it over to another xbox (I've tried both and this happens) for the other message however deleting worlds never fixes the issue even when I delete old copies of big worlds (600 MB) or so but I never needed to delete any worlds before a certain update that made me install a second version of minecraft, a version that transfers your files from the original to this new verion of the game 2 or maybe 1 year ago I don't remember, which replaced the original much better working version of the game.