If you render a muted audio element and set its source to the microphone's media stream, the audio element becomes unmuted automatically if you grab a camera track and set it to a video element. When this happens, the muted property of the audio element is still true, but you can still hear audio coming from the element. In this example, the audio source is coming from the microphone which is causing a lot of echo. I found this happening on my iPhone 11 iOS 15.4.1 using Safari or Chrome.
Please try it in this fiddle
1. Load the jsfiddle on iOS Safari or Chrome
2. Press the Mic button on the fiddle and allow permissions
3. Speak on the microphone. You should not hear any echo
4. Press the Camera button on the fiddle and allow permissions
5. Speak on the microphone. Noticed that you will now hear echoing and your voice
I was not able to reproduce on macOS 12.5 nor on iOS 16 beta.
I was reproducing it on 15.4. But I cannot reproduce anymore on 15.5
Thanks Charlie, I think this is bug 235544. Marking it as such.
*** This bug has been marked as a duplicate of bug 235544 ***