Put the summary of the bug you're having here

What I expected to happen was...:
I disconnected from my friend's realm and turned off my computer to go and eat dinner.  I got back on after I ate and expected to pick right up where I left off, which is what should have happened.

What actually happened was...:
Instead, I had lost 30-40 minutes of progress which was tough because I had found 14 ancient debris in that 30-40 minutes.

Steps to Reproduce:
1. I disconnect from the realm
2. I reconnect to the realm and lose progress.
This has happened three times now and they have all occurred in the nether since the 1.16 update released.  Two of the three happened when I was the only one online.