Okay..what type of evidence you found in logs that confirms SQL service was restarted because of Antivirus?

Which antivirus software & version causes cluster SQL restart at your firm?

what exactly you looking for on network setup?

Try T-SQL instead of GUI for restoring database.

They are Physical boxes..

I checked with respective team, but there is no disturbance found at network level or infrastructure level.

Event error log as below:

Cluster resource 'SQL Server' in clustered service...

Below is the output of netstat from SQLB node before re-start ( I have run below command to get the output)

netstat -ano | find "0.0.0.0"

SQL server exe :

...