Catherine Schell can be seen breaking character and laughing in two scenes - when Clouseau appears in his telephone repairman disguise, and later when he impersonates a lounge lizard at a night club (in the latter, she actually starts choking on her drink). These have been acknowledged as actual break-ups which were left in the final film.
When Clouseau poses as a telephone repairman and gets stuck under Sir Charles Litton's desk, most of the items on the desktop fall to the floor. But when the film cuts to the scene in which Clouseau turns the desk upside down, the items that were on the desktop are now on the floor and Sir Charles's desktop is clear.
As Charles runs away from the fat man to avoid capture by his guards, he first runs up the stairs where you see a fake punch against one guard then he hides and hits the second guard.
Then you see Charles sprint along the balcony to run towards the rope so he can escape to the lower floor. When Charles starts running on the balcony he hides behind a pillar and a stuntman continues the run thereafter. If you watch closely the stuntman runs too early. As the stuntman slides down the rope you can clearly see the secondary safety rope behind him.