Deliberate mistake: There is a shot of the huge Yogurt statue that is in slow motion. You can see that the smoke from the statue is rising slower than it normally would. This was obviously done to make the shot longer for Mel Brooks' voice over to fit.

Deliberate mistake: In the beginning of the movie, when Princess Vespa runs away from her wedding, she gets into a white vehicle. The next shot of the vehicle it is pink, then the next shot it is white again.
Suggested correction: The vehicle is never pink. It's always the same white vehicle. Maybe the light and shadows makes it look pink to you, but it's white.
It's never pink, but it isn't the light and shadows. It's the blue screen effect.