What made Brian opt for using such an ancient track for a 76 vocal? Why not re-record it? I love the backing track, obviously, but a re-recording would make the version a lot less frustrating.
Brian's heart undoubtedly wasn't in huge orchestral productions by this point. Sherry's vocals could even be a simple matter of Brian randomly finding the tapes one day in the studio and deciding to finish it.
Something I've found eerie - You can hear Brian's classic voice at the end of the stereo version, the one with no fade out. Sure, he's only speaking to one of the engineer's and not singing, but it makes a frightening contrast to the '76 lead that preceded.