I can't mix my App sound with other Music App on iOS

Hello,

My issue is the following. On iOS, I’m trying to mix my App with other audio App (for instance iOS music App).
I activated the background play for my App. I can start my App playing, switch to iOS music App but as soon as I start playing music in iOS music App, mine stops playing and as soon as I pause the music, mine starts again.

It used to work. I think it stops around juce version 4.2 but I also changed a lot my software I don’t know where the issue comes from. I just upgraded to 4.3 but it doesn’t solve my issue. the AVAudioSessionCategoryOptionMixWithOthers seems to be correctly configured.

Any idea ?

Thanks