He screws up in She Loves You right away by doing the 3rd verse as the 2nd verse, but it didn’t matter since Paul/George’s microphone wasn’t working until the middle of the next song so they didn’t sing over each other (you can see that they’re singing harmonies for the correct verse though)
And its a good thing that mic recovered since John used it for lead on Twist and Shout and that would have been awkward with a dead mic