Netbackup/VSS client launching VNX snap

I have a Netbackup 7.5.0.3 client launching a VNX snapshot even though the policy option "Perform snapshot backups"  is disabled. My guess is that even thought the policy is not set to do snaps the VSS 4.6 provider is finding the LUN on the VNX and then snaps and mounts the LUN on the local host to back it up. This client was originally set up to do off-host backups but now is not. How do I get this policy not to snap in the VNX and handle the "Windows Open File Backup" locally? My guess is to disable "Open File Backups" in Netbackup but then I will have trouble with the C & D drives.

Thanks.