This deal appears to be under the "beef" category. My friend has confirmed it to be working in Brisbane. It doesn't appear to be a daily deal, it just simply exists at the bottom of the "beef" section.
Working as of 2pm 25th May 2021.
I'm having trouble uploading the screenshot so the link is to the homepage of McDonald's. Might have to use the app because I'm not sure if it can be done in person.
Edit: working at the Fortitude Valley store through the app. Changed title to CBD and Valley stores where it has been confirmed. Not sure about other stores but worth a look!