Friendly mobs I've interacted with have disappeared

One day, I discovered that my villagers had disappeared. At first, I thought they might have been killed by zombies, but after checking my walls, I found no issues. So, I loaded a previous backup save and continued my progress.

At that point, all the villagers were fine, but after playing for a while, the same group of villagers disappeared again, as if they were destined to vanish.

Additionally, some of the pets I have, which I’m sure I interacted with, would also occasionally disappear for no apparent reason, even my armor stands. I have no idea what’s going on.

World download:

Before disappearing

https://drive.google.com/file/d/1-xc7lLmI8X0cWwYIbk93A6SqMlmIWpGs/view?usp=drivesdk

After disappearing

https://drive.google.com/file/d/1CU8djRB1PVQCOqLRfplFSI4WFsCz8ohq/view?usp=drivesdk