I can’t tell you the number of time’s I’ll click on my arrangement and accidentally hit a group layer’s volume section. Considering that nothing done in the arrangement window is recorded into the undoable history, I’ve now completely lost the volume of the group channel, and it is set to where I accidentally clicked (usually > 0dB).
I don’t know why these are at all visible, it should be a hidden automation layer if anything. But group channel tracks should have nothing or at the very least allow for undos on these. Selecting undo when you do this only removes the dot, but does not set the volume back to where you originally had it.