It seems to come and go. They "fix" it only to go back a few days later. I wouldn't hold my breath for anything permanent; if I recall when I had cable different channels had different volumes as well. It isn't worth getting worked up about, since a remote control fixes the "problem" instantly.
Charter Spectrum 60; d-link dual band router
Roku 4210, 3710; Xbox One, 360; Samsung BD player
Samsung tablet; Windows Vista laptop; LG phone
Toshiba DVD-R; Sony AVR; Panasonic AR
1080p and 720p TVs