Some ios users not hearing sound/music

Hey,

This is a long shot, I admit, but some iOS users are reporting that they either don't hear the sound/music for my game, or that they only hear it with the headphones on.  I'm using the latest adobe air SDK with a haxe library that's currently just out of beta (I'm not supposed to mention the actual library name in public) and the sound code in haxe is fairly straightforward and generic.  There's a *general* trend, though not 100%, of older phones having this issue (iphones 7-8 with ios 13.X, and one single iphone 12 pro as the outlier).   I'm not necessarily asking for a fix, but I would like to know if this is a known issue with adobe air apps on iOS. 

Thanks,

-Michael