I have the same issue with my Macbook Pro Retina going from Airbeam to VDMX or Madmapper really any Syphon client. But on my Late 2008 MacBook Pro it does work.
I tested Airbeam with my iPhone4s, iPhone 5, and also iPad2. All crop.
I emailed airbeam but they said they could not reproduce the issue.
@aoxleysm What is your system?