Based on CNM moderator comments, and also Canberra Times news story on 31 March 2019, I've edited this to be a breeding record.
Also two adults at the site.
https://www.canberratimes.com.au/national/act/they-re-a-rare-sight-in-the-act-and-now-we-know-where-these-birds-go-20190326-p517n6.html
Great to see that they are breeding successfully in the ACT :-)