Well there was an automation of the mute state on a reverb bus, meaning that it was the automation that that unmuted the reverb bus and all of the “supporting” channels.
Anyway thanks!
One has to question just how complex of a DAW do you develop until the DAW becomes counter intuitive? Today we have grouping, automation, linking, project vs mix console where its not always in sync, and now solo/mute issues. We have gone way past the best physical desks.
Try unselecting the “Group Channels: Mute Sources as well” option in preferences → vst. There’s also another pre-fader mute/solo option iirc, which may or may not apply here…but I find that the “listen” function is whole lot less confusion prone than “mute/solo”, especially when the routing becomes slightly complicated.