I’ve experienced it twice so far (both m+ runs) on the Myza’s Oasais fight.
Me selecting the horn (cause I’m a tank) and no musical notes showing at all during the fight. (neither during intermission or during last phase.
Not being able to get the buff is annoying esp. in higher key levels.
Had same issue yd, idk whats happening there but its quite weird . I noticed i dont see notes , and few seconds laters i couldnt even see boss name plate( with health bar) .
I was there once only so idk if its always buged or its some random stuff