Could you add "Edition could have bad ISBN, try another" or something like that to the help page, "Why do I see a message that a book record does not meet Goodreads catalog guidelines?" I run into this error message frequently and it is always resolved by switching to another edition. In several different discussions I've heard people complaining that they can't review their book. I even came here with the same question. If you suggest people try a different edition, I think it would help people so much. People are finding it really frustrating.
There is an issue with bots marking books incorrectly as invalid. In the situation you describe (book with ISBN set as invalid, but other edition with different ISBN is valid) there is a real chance that it is this problem and not a actual invalid book. So telling people to just shelve a different edition is not a real solution, especially for the part of the users who try to shelve the exact edition they have.
Thanks.