In the first two scenes, when the kids are in the school gym, the positions of the children change from shot to shot. Look at first two on the aisle in the first row, stage right: alternates between an older and a younger boy, and a boy and a girl about the same age.
At the very end of "The Song of the King" Joseph is seen at the top of the steps twice with his hand at his chin and in the next shot with both hands at his side, and again later with his hand at his chin.
When singing "Any Dream will Do" (reprise), during the lines "Give me my colored coat, etc" Joseph comes forward holding the coat in front of him. Two children dressed in red are standing next to Jacob and the Narrator. They are now behind Joseph. Just when the song ends, the cast crowd around him and then we see and overhead shot of a star. Joseph is now at the back with the two children, Jacob and Narrator in front of him.
During 'The Song of the King' Joseph says "I got the bit about the corn, but I'm not to sure about the cows. So if you could just give it to me one more time, Mr Pharaoh man." Pharaoh then proceeds to sing the verse about the corn
again, and not the cows.
This is in fact not an error. Pharaoh, an impatient man repeats the last line while Joseph checks for the correct answer in the Bible (held by the Narrator). The same is true for the stage productions.