Oh, I see looking at the code that you’re using the old deprecated AudioSessionGetProperty() and AudioSessionSetProperty() instead of the AVAudioSession that iOS7 wants; I guess it’s probably not just deprecated in iOS7 but actually just broken too. I’ll see if I can hack something together with AVAudioSession that works.
AVAudioSession is a higher-level wrapper on the older C-based AudioSession code, but the changes from OS to OS are not due to the API, deprecation, or being broken – there have been behavioral changes in these types of audio behavior in every OS since iOS 3 IIRC. The PlayAndRecord audio session has always had undesirable effects on playback since it was first introduced.
The VoiceChat-related skipping issue isn’t due to the audio API, BTW. It originates in the Pocketsphinx VAD, which isn’t designed to work with an audio mode that has noise suppression.