Since the bug fix for Realms crashing (REALMS-6812) we are seeing a consistent issue.
We have only noticed it at night, but in the morning when villagers wake up several of them disappear, villagers immediate create babies to replace them.
This appears to be the case across the realm and not just a single town.
The town I play in has 20 villagers and in the morning 5 of them are missing.
Like waking up in an M. Night Shyamalan movie. In the morning, the parents are replaced with babies 🙂
Occurs regardless of if the player sleeps or is awake
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is duplicated by
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Thanks for logging this in a separate ticket - would you be able to provide a copy of the world where this has happened? It would be really helpful in identifying the issue.
On Windows 10 you can use the Export world feature.
On Android or iOS you need to use a file explorer to navigate to Device storage > games > com.mojang > minecraftWorlds
If the world is larger than 10MB you can upload the world to OneDrive or a similar file sharing site, and then share the link.

In my case I don't know if it happens during the night but we have noticed that most of the villagers suddenly dissapear and when the rest start to create babies the server crashes loosing all the progress.
When the owner of the Realm download the world and play locally until the villagers stop creating babies and then upload the world again It seems the problem dissapear but It's not a solution.
I play on PS4 with 2 Friends.

I'd love to share it, but this one is on Xbox so I am unsure how to export it.
I will try to grab a video.

This issue is likely related to or a duplicate of this one:
John, thank you for the link - it seems that the sharing permissions haven't been set quite correctly though, so we're unable to download the world. (If you choose Share>Copy Link that should work.)

Lets try that again - https://1drv.ms/u/s!Am9O6HYEmrjjjcFNAAiXcU7bz2dS0g?e=CcoaZb

Since the 1.16.20102.0 patch we have reloaded our world from a local copy. The issue has not reoccurred.
Have you tried watching the villagers during the night to see if you can catch them in the process of disappearing? If so, it might be helpful to attach a video of that happening.