It’s possible they have an improperly created model.cfg file. They probably have a SimObjects\Airplanes\blahblah\model directory. You’ll find a model.cfg file in there. See how it compares to other model.cfg files, and if you find an irregularity, see if correcting that fixes it.
Technically, the Model directory isn’t needed anymore (depending), and you can remove the reference to the model.cfg file from the layout.json of the livery. See if that fixes it.
Edit: I just checked my N276ND livery (on flightsim.to), and it works just fine. I’d compare the structure of my livery vs. that one and see if you can find any differences to figure out what’s wrong. As I mentioned, it’s most likely a problem with the model.cfg file.