In the actual version of indesign (18.0) there is still an issue with internal generated vCard-QR-Code scanned by an iphone.
In germany there are special Characters called "Umlaute" (ü, ö, ä) or the "sharp s" (ß). If these characters are used in an vCard generated within the buildin function from indesign, they are replaced with other symbols on the iPhone QR-Code-Camera Reader.
I think this is only a Problem of the used vCard-Version. I think indesign uses Version 2.1 if you would just use Version 3.0 this issue does not appear.