It turns out that the primary iPhone app recommended by Google for scanning these decals was made by QuickMark. QuickMark had a bug that was introduced just about the time these decals came out. The bug impacted where users were taken after they scanned a QR code.
The bug was fixed yesterday and it now works perfectly for me. The bug fixes included:
- Fix incorrect URL bug
- Allow Move & Scale for Take Photo method
Forum discussion at Google Maps Help.