There are a few "audio instances" glitches in the latest so far version of the game, v1.1... So, the music is by default being set to start up playing when the pet is being chosen, and the room for that pet is being loaded... If a player chooses to mute the sound before entering the "Gym", then after returning to the room with a pet, the music is being reset, or, in other words, it starts playing from the start as if it never was muted, but just got reset... And it appears that if the player chooses not to mute the music before entering the "Gym", the game decides to start up a new audio as if it was muted, thus forcing the game to have the game playing two music instances at the same time, glitching up the sound of it... But the thing is, if repeated, there will be three, four, five music instances playing at the same time... And it can be done up to the infinity... And the only way to "clear" those music instances out is to "Mute" the sounds and then enter and leave the "Gym"... Thus initiating the start of a new instance which is to be used for music.