Created attachment 2751 [details]
For the 490 MARC field, the 'a' is the series statement and 'v' is the volume number. When displaying details on a biblio, Koha will display any fields in 490 in the order they are in the MARC file, rather than being smarter and making sure 'a' comes before 'v'. See the screenshot.
This applies to the XSLT and non-XSLT views, in both the OPAC and the staff client. Note that the link creation only applies to the 'a' field, so it's not causing breakage.
I think that Koha's behavior is actually correct, here. In 490, subfield 'v' could in fact come before subfield 'a'. For example, in the following:
$vVol. 5,$aThe Compleat Works of William Shakespeare, Abridged.
The good news is, that's almost never done. The bad news is, my understanding of the standard says that for the 490 (as opposed to the old 440 or the 830), that would be allowed.
Well, I think my concern was that it makes it look funny. I assume that we had a client who wanted it changed, though as there's no patch attached, I can't remember if I ever did "fix" it. Feel free to mark it as invalid if you like.