I just remembered that i had this fix applied before. Trying it again now, either it got vanished due to some update or at least something reactivated this behavior. I think I remember that I had undone this fix after some upgrade and it was working fine since but now it started again.
Comment out this line in /etc/pulse/default.pa
Code:
### Automatically suspend sinks/sources that become idle for too long
# load-module module-suspend-on-idle
I'll report back how it goes. Just had a blackout before and applied the fix now. If I don't get another blackout during the day I guess this fix is working again.