Some folders/files in a group folder sometimes are moved into the trash in error

Hi

We have a problem with NextCloud’s behavior.

Some folders/files in a group folder sometimes are moved into the trash in error.
Currently, there are many users in our NextCloud. So, to begin with,
I need to sort out whether it’s a human error or a glitch of our NextCloud.

Would you give me some advice about this troubleshoot in NextCloud?
(e.g., How to detect the time and the cause of this wired behavior using logs or something)

Does anyone help us?
I can provide more info as you need.