I just searched for The Last Olympian by Rick Riordin to add to my WL for my daughter.  It brings up 10 books on the search page, I add the first 1 and it says there are no other editions to add to my WL, even though I can see 10 right there.  That edition has "and" in the title instead of "&", so I submit a data edit to make it match.  I go to add the next one on the list, again it says "no more editions".  I add the 3rd version and that one brings up the list of 10. 

Just curious as to why if they're all connected under that 3rd version-they aren't all connected under the first two. I didn't look at any others because I only had 3 WL spots open right now.

I think it's just a glitch in the system.  You did the right thing by submitting the data edit.  Thank you!