This seems to be an issue when the app grid is set to “5” instead of “4”. Appears to work just fine on 4.
I’ve also noticed that when the Apple Music widget is used with the app grid set to “5” it does something different and cuts the artist name off completely.
I feel like nothing can do a bunch more of integration with their own widgets/glyph lighting for music apps like Apple Music and Spotify. It seems like a really big missed opportunity there right now.