I can't believe that my day is so empty that I actually got the DVD out to look...but I did, and you're absolutely right! Well spotted! Literally for about a second Patti is shown on screen wearing her long white coat with the black pattern...
She clearly sang the entire song in her plain black outfit so my (uneducated) guess would be that the shot of John fit better into that frame that the footage they originally had and so they cut that shot in but failed to notice Patti's costume change...either that or someone simply made a mistake, but it is there
