This was an issue with Bohemian Rhapsody too. I saw Queen live three times after "Night at the Opera' came out and each time the first half of "Bohemian Rhapsody" was played canned from tape and the band didn't step in live until May's blistering guitar solo.
By the time I saw Queen in concert, they had figured things out and only the middle portion was on tape, with the band playing all the rest of it live. Man, that was a great show, with Thin Lizzy opening.