I went into bunnings today, and sure enough, the victa long air filters are no longer the genuine ones. The last ones I bought (june/july 2018) had a little piece of paper in it, saying made on __/__/17 (don't remember the dates), and a couple of other things typed.

The GA spares ones from the mower shop also have this little bit of paper in the bag. Obviously the profit margin for Victa wasn't good enough, so they went with a cheaper supplier.