I had never used the “intercom” feature. I just tried it with the v2 camera in my garage. (I had to allow the Wyze app to have access to the microphone first, it is now back to being prohibited).
Here is my experience. I held the mic button down and said “hello”. Then heard the sound from garage 20 feet away. Then the sound that the camera’s speaker made, which the camera’s microphone picked up and retransmitted to the App. Almost like Amazon’s “Simon Says” function.
To me, that seems like a bug in the v2, at least when on same Lan. The camera should mute its microphone while it is sending audio out its speakers. I tried with my remote v1 camera, and it did not send the audio back, although there is a change in the sound being heard, but it is more like the sound of someone “keying the mic”.
Concerning the “screeching sound”.
If you watch a live stream and are standing close enough the camera you are streaming from for it to hear itself, you will get the “echo” effect. And if too close you can get the “screeching” sound cause by feedback.
If you just want to see the video, and don’t care about the sound, just turn the audio off in the playback screen (on the Android 1.3.113 app, the speaker icon is green/teal when enabled and grey with an x next to it when disabled). Alternatively turn your volume on your phone down or use earbuds; anything that will prevent the camera from hearing and retransmitting the audio back to the App.