After upgrading to NVBU 8.6.1, performing a general scan of a library: Device Management > Right Click library > Scan, only scans few tapes and stops the operation.
The amount of tapes/media scanned is equal to the number of drives present in that Tape Library or VTL.
This is a minor defect introduced in NVBU 8.6.1.
The defect has been confirmed by our R&D team as part of the defect ID NVG-6720.
This will be addressed in a future version of NVBU.