Good Day Andrew
If i get you right, you are using HP Data Protector 6.10 and you have a client you backup on which Windows Server 2012 is running? Please be aware that DP 6.10 is not supported to backup windows server 2012 System.
1. if you enable the vss writer option during file system backup, dp does trigger the vss writers on the client. as far as i know this does result in accessing vss writers for sql, exchange and so one
2. you could disable vss for the file system backup, but normaly it is needed for dr purposes.
-> go to the file system backup from the sql server, in the tab "backup object summary" select the client, go to properties and check und "winfs options" if vss is selected. if yes, this would explain why sql vss writer is triggered during file system backup
Checked on a 2008 r2 Server system with SQL 2008 and DP 7.03. File System VSS option is activated. If you look at the dp session log from the drive on which the sql db resiedes, you can see vss entries for sql db backup. if you open sql server management studio, go to a db -> tasks -> restore -> restore files and file groups you can see all the backups taken. there you would notice also backups from dp. they should have status "copy only". this backup type does not interference with the full/trn backup you do with the sql maintenance plans.
regards
andre