I’ve had this issue (or similar), and reported it here:
https://www.steinberg.net/forums/viewtopic.php?f=230&t=89318
No confirmations, despite reading other threads of the same issue and no-one had reported it.
I’ve mentioned I’d happily send the project to them for investigation, I’ve had no contact about it.
Has anyone else who’s suffering this issue found that they get audio when above 0dB and none below? Seems related (it happens to me in 8.5 and 8.0.30, but not in 7.5), but maybe it’s another issue.