Sound volume icon is glowing red

Had the same issue, it seems tied to the tab button. If you tap tab you'll cycle through the other buttons on the miniplayer (where this problem was for me).

Shift + Tab resolved the issue, but only if I don't quit the app.

So this is happening on most if not all my entertainment apps on the laptop, tab may move it to the play button (which should be what spacebar does normally), but it SHOULD NOT be highlighted by default without explicitly tabbing through the controls.

apple, please fix this issue.