Defect: Modify Audio Channels of 4 channel clip to 2 channels, all 4 show up in sequence
See attached video.
Select merged clip with 4 channels
Select clip in Project bin and modify audio channels
Make all mono if not already
Deselect 2 of the channels by unchecking them
View audio of clip in Source Monitor (shows only 2 channels, as expected)
Drag clip into empty timeline to create sequence.
All 4 channels are present.