Just spent a week in Sydney and every incoming call had no incoming audio. I was answering phone, hearing nothing and telling them to phone back which they did with incoming audio the second time. This happened 5 or 6 times.

Then I started getting incoming calls where there was audio but it was someone elses phone call. Full on conversations with Aust accent talking about being in Christchurch which is where my incoming call was coming from.

Really weird.

In Melbourne didn't have any issues, incoming audio every time I had a call.