Wearsafe Rewind cannot ready audio while other apps are recording, such as video recording or VoIP chat apps. It also cannot ready audio if you have denied microphone permission.
On Android, well-behaved apps like Wearsafe will hand off control of your microphone as necessary. Some apps may not work correctly with the microphone while Wearsafe Rewind is enabled. Those apps may not take control correctly from, or release it correctly to, Wearsafe.