When you sign out and sign back into your Xbox profile while still being in Minecraft Bedrock and then enter a world, for keyboard and mouse controls you cant move your head with the mouse but you can still move your character with your keyboard and you can scroll through the hotbar with your mouse. In past versions you could sign out and sign back in with a keyboard and mouse and have no issues. Real issue for keyboard and mouse players. Only happens in version 1.13.0 of Minecraft Bedrock Xbox One.