So, I tested it. :) You just have to give the PHONE permission to the AOSP launcher, and the shortcut works. It's badly coded by Google/AOSP on that part, it should ask to be granted permission, not to say "the app isn't installed".
Thanks for ...
I have the same problem, but it hasn't happenend very often so I haven't really cared. I don't know what fixes it, just wanted to let you know that you're not alone on this ;)