Have you installed media server software on clients and configured as SAN media servers?
If not, and your clients are writing directly to HPE, then backups are probably not scheduled through NBU, and NBU has no knowledge of the backup.
Can you confirm how backups are configured in NBU policies?
What is policy type and Storage Unit?
If backups are scheduled through NBU, and clients are NOT configured as SAN media servers, then data flow is :
Client > network > Media server > FC > HPE
For SLP backup and duplication, the backup process will be as above, followed by duplication:
HPE > FC > Media server > FC > Tape