One and same book listed twice - why not merged?

[Tim]

I don't know if this is the right place to post it, but it concern an omnibus of a series, thus...

The Once and Future King by T.H. White is listed twice (!): once as 1-4, once as 1-5.

The 1-4 link: https://www.goodreads.com/book/show/2...

The 1-5 link: https://www.goodreads.com/book/show/2...

But it is one and the same edition. I checked with my copy (which has all five stories, thus 1-5).
ISBN-10 = 0008108587
ISBN-13 = 9780008108588.

A friend of mine, a Goodreads Librarian, told me there was a notification NOT to merge these books.

But if it concerns the same (!) book, why may it be listed twice (once correctly, the other erronously)?

Thank you for shedding light on the matter. :-)

[Abhijeet]

Hmm, I looked it up: http://www.isbnsearch.org/isbn/000810.... It confirms your information above. I'd be interested too in understanding why the situation is the way it is :)

[Arenda]

Both links are indeed for the same book. One has the isbn10, the other the isbn13.
Merged them into one edition: https://www.goodreads.com/book/show/2...

Both the 4-book edition and the 5-book edition have the same name (The Once and Future King). The librarian note was not for this specific book, just a general remark: only combine 4-book editions with each other, and 5-book editions with each other.

One edition was incorrectly combined with the 4-book editions.
Worldcat also confirms this is the 5-book edition.

[Tim]

Thank you for clarifying and rectifying this issue. :-)