I'm gonna guess this latest updated did something the audio for a few games. Currently using a Samsung Galaxy Note9.
-Pokemon Yellow Version
>Can't hear Pikachu say 'Pika-chu' at the intro + the sound affect with the shooting star to say 'Game Freak' sounds very off nor does it have the starry sound affect
-Pokemon Red, Blue
>Shooting Star that'll display 'Game Freak' has no sound when starting the game
-Pokemon FireRed Version
>Slight occurrences of crackling sounds
-Yu-Gi-Oh! Duel Monsters International 2, Yu-Gi-Oh! Duel Monsters Expert 3, Tennis no Ouji-sama (Prince of Tennis) Glorious Gold, Tennis no Ouji-sama (Prince of Tennis) Stylish Silver
>Crackling + 1 or 2 second delay as the music's playing
That's pretty much all I've noticed so far
I've tried an handful of enabling/disabling features to see if anything will make fix the audio. Unfortunately nothing's worked.
Hopefully the next update fixes the sound issue~ Thanks !