It's "I'm Looking Through You.

Yes—the false start is on the final master of “I’m Looking Through You” from Rubber Soul.

You can hear Paul McCartney count in “one, two, three, four” and then a quick “oh” before the song actually kicks in. The band liked the energy so much they kept it. The whole take was recorded in one go, which was rare for them at that point.

It’s one of those happy accidents that makes a recording feel alive.