Rhythmbox isn't functioning well in Fedora 35.
In Fedora 35, Rhythmbox issues two instances of a notification when a song is played.
More issues occur when using the media keyboard button, when manually changing tracks or changing position in a track. When the aforementioned actions are initiated, the audio may either completely cut out or the audio begins to intermittently cut out.
The issues are present in Fedora 35 with Rhythmbox version 3.4.4.