Walked past a HJ today and decided to play shake & win. Got a free fries so I went in to redeem it. The app gave me an option to redeem it via the app (which seems to be a new feature). When I tried that, it said I needed a min $1 purchase. Then I noticed that there is a new condition on the prize screen. (Forgot to take a screenshot.) Didn't have time to try to see if it's possible to bypass this requirement by redeeming at the cashier. (Would be good if someone can try and report back.)
Not sure if the same condition applies to the free soft drink prize.
All Shake & Win prizes (including the ones where you have to pay) now require $1 min purchase :(