Ok I guess it was a fluke, I am very well versed to say I wasn't making it up/ misread blah blah. There was a clear movement of 4-6 people from Comfort to biz at the time I was looking. I wasn't looking too much at economy but maybe it was full.
I have seen other circumstances with other airlines that if you for example are looking for award space on QF and happen to search the 3 mins window when status upgrades are happening you can slip in and grab a seat - very difficult.