Third-Party
This has happened on a number of occasions now, where I have gone in physically to a Repco store, they scan my trade card, I pay using credit card, then the next thing I know in the car park, I get an email from CR saying they have tracked my transaction!
How does this happen? Not that I'm complaining of course - it's awesome that it happens automatically! So far only Repco in my experience has been like this.
https://www.cashrewards.com.au/in-store/howitworks
You might have linked your card way back when and completely forgot about it.
(I did the same lol)