I use the website rather than the app, and cards haven't been linking correctly for the last month. At first I thought it was just an update, Khans cards or a weird glitch, but I have tried on my phone (Android through Chrome), my tablet (Nexus through Chrome), my laptop (Windows 8 through Firefox), and a desktop at work (Windows 8 through Chrome) and none of them work.
hmm {Cryptic Command} i'm not sure if it is working for me on my mac