I have been experiencing similar issues. The audio just seems inconsistent. It often doesn't play or sometimes it is perfect and I can't work out why.
One thing I've notice is even when you only compile for Android the APK export still contains .ogg and .m4a files. I've started deleting the oggs from the zip file, which has saved RAM and file size, but doesn't affect the inconsistency of performance.
It happens even when FPS is quite high and the game is running smoothly. The sound clips are all small (less than 1 sec at 96Kb/sec ), with a maximum of 20 on any one layout).
Results so far have been the same on:
Samsung Galaxy S1 and Samsung Mini both running Android 2.3
Google Nexus 7 running Android 4.2
HTC Evo running Android 4.0
ludei, I noticed on your forum back in December you were planning to re-write your audio engine. Please could you give an ETA (or how high it is up your priority list) of when these audio problems are likely to be fixed?
Our current game, soon to be released, relies heavily on audio, and it really is a priority for us.