cubase 9.5.1 Output dissapear problem

Does anyone have this problem ?

Cubase 9.5.1 , window 10 , fireface ufx

If i create a group channel , Output (Stereo out) disappears with a 3~40 percent probability
after it disappears , the volume suddenly shrinks by half .
if i go into a audio connections - outputs , stereo out bus button is disappear
so i restart the cubase , make a new stereo out , and i need to reset the output of the tracks
so annoying …

Is there anyone helping on this issue?

I just ran into this problem and realized I had accidentally moved the “Stereo Out” track channel into a drum track folder. I opened the folder, moved the track to the bottom of the project, and BAM it appeared in my mixer again. Hope this helps others.