If you create a world when your logged out, after you create a account the worlds will dissapiar if account is on diffrent device.

Example is on the 123 phone i had a world without a account. On device 123 i created my own account and could play my worlds. Now i decide to log in on dwvice abc. Abc will have no worlds no achievements or anything i earned on the same account on device 123 so everything is gone. 

Steps to reproduce

1. Create a world without being logged in
2. Create a account
3. Log into the account on a diffrent device

Observed results: the worlds will be gone on the 2nd device but still there on the first

Expected results: the worlds will be there on both devices playable and everything

Side notes: the device i made the account on never had a account same with the email i put in. The first time i logged in i played a bit on my world. Then i logged in on a diffrent device that had a brand new minecraft first time ever.