No sound in Halion SE - strange reason

Hello, recently it happens quite often, that I get no playback sound of my scores.
I normally go to Play Mode, choose my Playback Template again and „Load Sounds for unassigned Instruments“.
Still I can only hear f.e. one line of the instruments.
I open the Halion SE Window and get something confusing, see this screenshot:

It seems to the very right something must have automatically changed the Output from „Main“ to other ports.
If I put them all back to „Main“ I will eventually get my Playback working again:

Is there anything I should be aware of? Why is this happening?
ps: I normally don’t visit Playback Mode at all, my focus is on writing. I will check visually and occasionally by listening to the audio. I use the Key Command „P“ - I don’t bother with Play Mode actually…

That the slots in HSSE are routed to Main, Out2, Out3, etc. is actually right, because Dorico has an own mixer that mixes all of them together to it’s own master channel.
It seems to me that the Dorico mixer is messed up somehow with you. Could you please post a sample project (one that seems to be broken) here or send to ‘u dot stoermer at steinberg dot de’? Then I can take a closer look. Thanks