I’ve always had the audio issues as well.
I have an older multibridge-extreme in a mac(thanks for still supporting that driver bmd)
and now also a decklink studio in another mac.
The only issue I have is audio lag.
If I hit play to start with a yellow line in premiere, it’s way off synch.
if I stop and restart playback its fine.
It’s been very consistent from the get go. going back to cs 5.5
I suspect this is a mercury transmit issue at the heart of it.