Documentation on issues with backups

Recently I read some Fortinet documentation which stated that running a backup from the Firewall itself can or will cause any sessions on that Firewall to be broken. Whereas backups run automatically from a Fortimanager do not have that same issue.

I have since been unable to locate the documentation which stated this and I need to get confirmation on this issue.

Can anyone confirm that sessions are broken when running back-ups from the Firewall itself but not when done through a Fortimanager, and/or, can anyone point to documentation that states this fact?