I went on the Mummy twice and each time there is a projection of Imhotep saying 'Your Souls are mine' - is there supposed to be an animatronic at this stage?
The mummy that says "Your souls are mine!" is supposed to be a projection, as your railcar gets launched into his mouth.
The two animatronics that can have "alternate shows" are the first mummy (the one that kills Reggie) and the one in the fake unload. All others are supposed to be projections.