I was checking daily for a while, and never saw the direct YVR-MEL. Although I did find some nice connections on SQ, every time I tried to book I got “Sorry, seats are no longer available”. This “ghost” SQ availability was all in late November early December, so that is where I focused my search - plus, it is close to summer too.

Then I was just checking occasionally on my PC (the initial searches we’re on mobile. Then, voila... it appeared. I assumed it would be ghost availability again, it it went all the way through and I got all the necessary confirmations.