Here's what it was. I changed the background color in PRV to white, and so muted clips essentially disappear. God, that's like a two-line code fix. Don't they QA these things????
Unheard Voice in Wilderness Chapter CXVIII: Sonar has gotten much too cute in color management. It is unnecessarily complex, suffers from bevel-itis, and often there is no satisfactory color solution. There should be a mode whereby the user can get rid of distracting bevels and tell Sonar "I don't care what colors things are. Just make it easy to tell stuff apart"