I joined my cousin, who was on an iPad, on her world, using our Xbox accounts. We did not use LAN. After leaving the world, I was forced back to the title screen. I noticed that the background was black instead of showing underwater images from a Minecraft world. I was very confused by this. After exiting and re-launching Minecraft, this bug went away. I joined her once again and left, and this did the same thing. This is not a very major bug, but it would be nice to have it fixed. Thanks for taking the time to read this bug report.
(p.s.) If you were confused, yes, I can still press buttons and see everything except the background. Look at the image below if you want to see what it looks like when this bug occurs.
Thank you for your report!
However, this issue has been closed as a Duplicate of MCPE-34226.
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