Sound failure on Asus Fonepad 8 FE380CG

We have a simple quiz app that was distributed through ad hoc installation (Using APK) over 100+ devices, but when playing with the playback sound (muting/unmute/increasing volume/decreasing volume) roughly 5 percent of the devices will hang and crashes.

We're not sure what the cause is, if somebody has any solution please let us know.

Mobile platform

Asus Fonepad 8 FE380CG

Model Number

K016

Android Version

4.4.2

Compiler

AIR SDK 18.0