Could be that the mobile devices you were testing on don't have the horsepower to play the music at the same time it's rendering the game.
But it really comes down to one important question, are these problems appearing for you in PREVIEW or in EXPORTED versions?
Because I've had tons of problems with audio in Preview, even submitted bug reports (but Ashley kept dismissing them, even though I eventually got it to under 40 events, kept saying it's still too much).
For me, the audio usually works in Preview if it's browser, but if I use NW.js it can derp up. Haven't tried any mobiles though.
I know that debugger usually gets the sound playing correctly, at least in browser preview.
As for export, no bugs there. Yet.