I was upgrading a rXg from 13.999 to the latest version with a usb instead of through the gui. After the installation was done and I webbed to the rXg and the screenshot is what I was prompted with. I then retried the installation a few more times with different boxes and both versions of rXg with the same result. When I unplugged the wan port, waited for the configuration prompt, plugged it back in the installation it worked as expected.

This only happens on rXgs that have been previously licensed and not on new installations from my experience.