Windows Sync client constantly syncing all files

Nextcloud V 13.0.1
PHP : 7.0.28
mysql 5.7.21

External CIFS shares connected from Windows Server 2012r2

A lot of Files.

Hi there.
Hope anyone can help me.
It seems the sync client never ever stops syncing.
Without changing any Files the client is syncing complete shares again after minutes.
Whats wrong and how can I solve this?
The Problem exist on different Clients, so I think its a Prob of the Server…
Thanks!
Basti

Edit:
Nextcloud 16.0.5
PHP 7.3
Mariadb

Complete new Installation of Nextcloud Server and Sync-Clients.
All Nodes sync with the Same NTP Server
Same Problem! Clients Sync whole SMB-Connected Shares without any change in the Files.
Is that a normal behavior - can anyone tell?
How can I check what changes were detected in the SMB-connected folders?
Please Help.
Kind Regards,
Bastian

Is there any problems with time sync between the servers?

Other than that I’m not sure. Did nextcloud have write permissions on the files? I believe nextcloud is using mtime. Perhaps something is off on the mount?

Thanks for your Answer. All Server sync to the same (internal) NTP and there is no time problem I think. I’ve checked right now and both are exact (within 1 second) synced.

Any other Ideas? I’ve a few Customers with the same setup and all of them have this Problem as far as I know.