Due to the two-camera technique used to film most of the scenes, during much of the performances the audio does not match up with the performers. One such example is during the Suzy Parker segment, and again during I Got a Feeling, though this scene was filmed using five cameras.
The production crew forgot to synchronize the cameras and audio recorders with time code allowing each piece of equipment to run at its own speed. This is the reason audio and visual are out of sync.
At one point rehearsing "I've Got A Feeling", John is heard singing (and bantering) with Paul, but his mouth isn't moving on camera.