Older TVs used to have this issue with commercials. TV shows would only run on one speaker and the commercials were in stereo and would run in two. So the TV show would be fairly quite, but as soon as a commercial came on, both speakers were used. It was because it did not have the correct wiring between analog and digital.
Not sure if commercials is the ops issue but for the discussion above, here in Australia adds are purposely set louder so those grabbing a quick fix from the kitchen can still hear. Its denied of course. Talk back radio talk about it often on tv subjects, they denying the volume is louder is total bs and annoying. All broadcasting here is in stereo.