12.3 issue with rescanning for new backups in GFS jobs

[mkretzer]

Hello,

I wonder if it still makes sense to open a 12.3 ticket or wait for 13 upgrade:
After switching to LTO10 we changed our tape scheduling so our GFS jobs start while the source jobs are still running (source job creates synthetics so the tape job can then just take them). According to documentation this should lead to the tape job waiting for the backup files appear on the source job.
This "works" so far but it behaves strangely/not good: We have 3 drives writing and even a day after all synthetics are available some job components still show "Some backup files are locked by the backup job, waiting for availability..." and "No backup files found". Then, after the currently writing backup job component finishes it does the rescan, finds the next set of VBKs (but only from one source job) and starts writing them to tape.
Problem is some of these backup components have one one VM in them which leads to the backup job using only 1 or 2 drives and the others drives are "idle".

Is this a known 12.3 inefficiency or should we open a case?

Markus