I don't know what happened or how can I test to find the cause of this. But the toast doesn't pop up or show anymore when a song plays, neither when using a disc on the juke box.

Which version (minecraft and the mod), and if you are playing with another mods, can you provide a list

the same is for me, MC is 1.21.4, MusicNotification is 2.3.0. After testing it seems like that in my case Advancement Plaques is the problem. any chance for a compatibility patch?