Other mistake: In the 'Macavity' dance, Demeter makes a mistake with one of her moves and makes an "Oops." face.
Other mistake: During the Journey to the Heaviside Layer song, Old Deuteronomy and Grizabella climb the steps to the tyre twice. (01:44:55)
Answer: It's a bit vague, but when Grizabella was young, she left the other Jellicle cats, turning her back on them to live another life, thinking she was more glamorous than the others. Now that she is older and has fallen on hard times, she returns, wanting to rejoin the tribe. The other cats are resentful that she considered herself better than them, and they are put off by her shabby appearance, so do not want her back.
raywest ★