Sometimes sound engine is not muted during phone call(android).

Question

Hello

our team is developing ios/aos mobile game using Wwise Unity Intergration with SDK 2021.1.11.
and we noticed a problem related to audio focusing behaviour during phone call on android mobile platform.

we want our app's sound always be muted during phone call,
but we discovered that in some cases, it does not.

When we recieve phone call during gameplay, the sound is muted at first (as we expected).
however, once the app goes background and return to foreground during phone call, the game sound gets unmuted!
(but it plays with small volume.)

it seems to be related to "Automatic Ducking" on android... but we are not sure whether it is controlled behaviour by wwise or not.

https://developer.android.com/guide/topics/media-apps/audio-focus#automatic-ducking

so there are my questions:
1. is there any option disable 'automatic ducking' behaviour on aOS platform?
2. or is there any other way to make our app always muted during phone call?

thank you.