Folders go Mute when all tracks inside are solo'd?

There is another bug with muting/soloing. Try to mute group1, then solo group2, and then try to solo group1 too… it will be displayed as soloed, but you wont hear any audio coming from group1. Has to be something with the mute action you did before!

Steinberg have no interest in fixing this - it’s been like it forever.