I've had a realm since about the start of December now, and I've only had some minor problems, until now. This has happened >3 times now. Me and my friends will log onto the realm, and start playing. Then, anywhere from 1 hour to 3 hours later, the realm will randomly disconnect you (bring you to the dirt screen that says "Disconnected from server"), and when you try to rejoin, everything is rolled back to exactly the moment of when you first joined the server.
I've encountered this glitch firsthand on my Windows 10 PC, both the client and realm on 1.16.201, but my friends have encountered this on Xbox and mobile as well. It seems to be a server-sided problem.
Related issues
Comments

Thank you for your report!
We're tracking this issue in REALMS-6812, 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 – 📖 FAQs
-- I am a bot. This action was performed automatically! Please report any issues on Discord or Reddit