Having the same problem, MM doesn't even show my 4 audio chromecasts units. It does show, and cast to video units. VLC has no problem showing and casting to either audio or video units, or groups. I have confirmed this on 2 computers so it doesn't appear to be a system issue (I checked settings ...

March 2021 and this still exists. 1. Running current versions of the pro app. 2. It only happens with MM. Tested other player apps (Youtube Music and VLC)and they do not have this issue. 3. It appears to happen when the volume becomes low. If I lower the column control in the middle of a song, it ...