They are very careful not to state parts of the panel spec that they don't absolutely have to, then they can legally (though obviously not morally) change the unstated parts without any issue. With early review units there are other extra excuses available to them.
It is rare that a screen will get such a significant downgrade, though it has happened. More common is downgrades in RAM and drive performance. Drive makers themselves play fast and lose with this sort of trick, sometimes changing both controllers and memory to the detriment of performance multiple times without outward change in product codes.
How is this not fraud?