Other mistake: The manager mentions that he is going to be on the late show on Friday and the "Meetings of All Meetings" on Saturday. In that meeting, the mention of the late show happens when it was supposed to have already taken place on that Friday after going to Liverpool. While it was a dream in the movie, the appearance was still supposed to happen. In the deleted scene, the late show happened but then this would have to have been before Liverpool instead of after, since this was a possible motivation.
Other mistake: When Jack and Rocky get on Ed Sheeran's plane, they are carrying 2 guitars. After the Moscow concert, before the 'song challenge', Ed says Jack wrote 'Back in the USSR' on a 3 hr plane flight with no guitar on the way to the show. (00:37:38 - 00:38:38)
Answer: Believe it or not, the Beatles did not invent the idea that a submarine could be yellow, and yellow toy submarines were sold for children to play with.