I don't believe they were using QR codes at all. They just printed the wrong URL, which they still could have done when using a URL shortener. And if you were

I don't believe they were using QR codes at all. They just printed the wrong URL, which they still could have done when using a URL shortener. And if you were going to use a URL shortener, you want to use one that you either have a vendor relationship with or you own the domain. Otherwise the shortened URL could change to something and you'll have no control.