For iPhone Beta and Mfi users, iOS 13.7 seems to have fixed most of the iOS audio routing issues, ones that would cause the iPhone to lose communication with the aids or stop responding to the iPhone’s aids control. In previous iOS versions, Phone calls would result in one or the other aid not communicating, and sometimes the incoming call would not route to the aids, but go into a hunt mode where it couldn’t decide where to send the audio - speaker or aids. Also, in 13.6 and earlier 13, there were problems with the phone changing volume levels when switching apps.
Also, for Resound Smart users, the app now maintains communication with the aids when it is not in the for front. It seems to override the built in iOS aids controls, so it seems like both cannot be active at the same time.