There are a lot of people who are financially conservative, but socially progressive. A lot of these people are former Liberal voters, but who have been turned off by the hard-right Lib policies. As a result, they're switching to the Greens, rather than to the ALP. Presumably, their historic allegiances are still strong enough though, for them to preference the Libs ahead of the ALP.What I found interesting when I have counted votes in the past and these numbers support it too, about 20% of Green votes direct their preferences to Liberal.
There have been quite a few seats recently, which have switched from Libs to Greens (or Teals). A lot of formerly safe inner-city Liberal seats are now going Green, rather than going to the ALP.