Looks like it's all around with the QF aircraft, the early Dash to Willy is late as well, it's usually the first to get frosted parked out the end of B finger.
This happens every time there is a frost in MEL. Been happening since at least 2001 when I started at the airport.
The anecdotal story is that deice fluid isn't allowed as it will run off into some creek and pollute it - but if DJ are doing the squirty thing then that argument is moot.
Last big frost a month or 2 ago they were boarding the QF aircraft and towing them down to the Golf apron for deicing (at least that was what it said on the screens) - I never got down there for a look as one of the frosty Dashs decided to have a fuel leak as well. So I don't know what sort of setup was down there and who was doing it.
I've seen some creative solutions from the QF engineers, like using a huffer cart to hot air deice the wings. They had an old deice machine as well that they used to fill up with hot water, but seeing as the heater unit had been removed long ago, the water would be lukewarm at best by the time it got to the line - and no deice fluid to stop refreeze. It may work but it's not really a legal approved method, and therein lies the catch.