The only reference to this issue I can find is for file backups when the backup plan has duplicate files / folders selected for backup. This can happen when you specify a Users folder dynamically for backup (e.g. %userprofile%\nicholas) and then also have a file or folder in the Nicholas Users folder selected to backup as well.
If this is not the case, then reply back with the information requested above and I'll see what I can find.
The current version of the agent is 7.6. You’re version is long out of support. I would strongly encourage you to upgrade to a newer version and see if the problem is resolved. You can find the Product Lifecycle here: https://www.msp360.com/ProductLifecycle.aspx