For the bit of the drunk waiter getting pushed on the dinner table by the opening kitchen door, Hrundi's full wine glass has been removed (probably to prevent staining the white table cloth). The water glasses also are arranged so they are not in the way of his falling. After the head waiter chokes him, a red wine glass appears on the table for the drunk waiter to pick up and drink.
Mrs. Clutterbuck falls from a walkway into the swimming pool below and is pulled out soaking wet. She is carried up to her bedroom, but her clothes are now dry.
The sax player is playing a tenor for the whole film until the end during the bubble scene, when he is playing a beaten up old C melody. He clearly didn't want his horn to get ruined. It would have been better to use something else, as it's a completely different instrument, different keywork, different color, and different size.
When Hrundi (Peter Sellers) arrives at the party, there is no license plate on the back of the car. Later, when he and Michele (Claudine Longet) drive away from the party, there is no license plate on the back of the car, but the license plate is back when he leaves Michele's apartment.
All cast lists, Closed Captioning, and C.S. Divot (Gavin MacLeod) introduce Michelle as Monet. However, when Michelle introduces herself to Hrundi, Claudine Longet says her name is "Michelle MANET." It is unknown whether this a mistake or it is supposed to illustrate that Divot doesn't really care who she is, as he is a casting couch predator.
After Bakshi (Peter Sellers) enters the house, soaked from the garden sprinklers, the make-up around Seller's eyes begins to run visibly.
During the dinner scene, when Peter Sellers is about to cut into the chicken on his plate, the chicken starts flying off his plate before he moves the knife down to cut into it.
When Bakshi lifts the lid on the toilet cistern, it is full of water. If it was continuously flushing, it should be empty.
When the Cowboy gets shot in the forehead with the toy gun by Peter Sellers, the scene with him getting shot is shown in reverse, as the fire flames can be seen flowing downward.
There is no reason for the bidet to leak. Whilst the toilet breaks down after Bakshi has used it, he has not touched the bidet before it begins to gush water violently.
Mid-way through the film where the woman is playing guitar and singing, the sounds of the guitar strings are not in sync with her finger plucking. There also are sounds from other instruments, like a flute playing along with the music, yet she is performing solo with only the acoustic guitar.
After the scene at the beginning of the movie where the director is chasing Hrundi for blowing up the fort, there is a shot of the rubble. In the lower-left corner, you can see the moving shadow of a crew member. Using the scale of the person's shadow it is apparent that the fort used in the explosion was a model and is rather small.