Repro: 

1) run media player, e.g. Rhythmbox (affects anything really ��� Podcasts,
Lollypop, you name it)
2) play some track
3) hit "play/pause" media key (that's how it's marked on MS Natural Ergonomic
Keyboard 4000; it's called "Audio play" in GNOME's keyboard settings)

Expected: the playback is paused

Instead: nothing happens, also text inputs lose focus for a brief while

Remapping "Play (or play/pause)" key in keyboard shortcuts do something not
involving media keys doesn't change the outcome. Pressing "Play/Pause" in xev
window doesn't produce any events except losing and acquiring focus.

The issue has been introduced sometime GNOME 3.32.1