Not something that I can recall having seen in Sydney, but perhaps I haven't been looking. Or, perhaps, it's down to the colder weather in Melbourne, and probably the frosts that would be concomitant with that.

I noticed a number of leaves like this one. On one side, they look just like normal autumnal leaves. But on the other.... they've been completely bleached white.

I don't think that intense sunlight is likely to be the reason. As I said, this is Melbourne.