Some Apps And Features That Use The Internal Microphone Do Not Work Properly When Audio Playback Is Through An Airplay Device
After transferring audio playback to an external Airplay-based system, apps and features which use the microphone on your iOS device may not work properly.
This problem has been encountered with Siri, voice dictation, audio messages in the native Message app, and in some 3rd party apps.
Typically, the listening tone will be heard, but immediately followed by the stopped tone.
Bug First Encountered
Device(s) bug has been encountered on
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The only way to solve the problem is rebooting the device, because the problem remains even if audio playback is switched back to your iOS device.