I don't know about that particular model, but while I was researching purchasing a cabinet incubator the variance in temperature on each level is an issue for many models. Definitely a good starting point for troubleshooting before future hatches! Hopefully temps were just a little low and your...
I looked up the model, all I saw was a large cabinet style incubator as a "pro" version. If that's the model, have you checked temps at each level? And which level are you holding these particular eggs?
That's a bit of a puzzler. I would tend to think your incubator is running cool, and maybe they are behind on development. What is your set up? Do you have secondary thermometers that are calibrated?