The menus are only as accurate as the day they are put online. Almost all Disney menus are printed on paper and many are dated. They CAN change from one day to the next. There is no guarantee that the menu item you saw online Monday morning will still be there for dinner Friday night.
Of course, some menus change very little in months--others, like California grill, can change from one night to the next.
As an example, the "official" CG menu I just read online today is NOT the same as the menu we had when we ate there 2 weeks ago!!