My brother plays Minecraft on his Nintendo Switch and joins my world on Xbox. About thirty minutes after joining, every GUI takes forever to load or fails to load completely. For example, opening the inventory, a chest, or using a crafting table (anything that brings up a GUI) hides the inventory bar and a loading bar appears across the screen. He is unable to move his character or interact with anything until the GUI finally loads or his game crashes. The connection, however, still functions, as he can still see my character waking around and interacting with blocks and objects.
Related issues
Comments

Thank you for your report!
We're tracking this issue in MCPE-111640, so this ticket is being resolved and linked as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki