New to voice demo app weirdness

So I have run the demo that come with voice like so:

On MacBook Pro in Unity editor and an Android device
On two Android devices

And the results are always the same...

Player 1 talks to player 2, player 2 hears perfect audio

Player 2 talks to player 1, player 1 always hears a distorted very noisy response

I have implemented PUN into my app and now feel voice is required and happy to see Photon supplies this, but not sure if this is right if I get this result on your demo?

Please advise?

Thanks