1. https://en.wikipedia.org/w/index.php?title=Emscripten&oldid=707816656&veaction=edit
2. Select the last reference at the end of the "Software Archiving" section.
3. Press "Convert".

Actual:

After conversion, the url no longer works correctly. The urlencoded colon in the url has been double url-encoded (from %3A to %253). The colon in the link label also got url-encoded for no apparent reason (it's not a url) - from : to %3A.

Internal wikitext of relevant portion from this revision:

Before:
Wiktext

<ref>[https://archive.org/search.php?query=collection%3Asoftwarelibrary_msdos&page=1 collection:softwarelibrary_msdos]</ref>

Link https://archive.org/search.php?query=collection%3Asoftwarelibrary_msdos&page=1
Label "collection:softwarelibrary_msdos"

After:
Wikitext

<ref>{{Cite web
| url = https://archive.org/search.php?query=collection%253Asoftwarelibrary_msdos&page=1
| title = Internet Archive Search: collection%3Asoftwarelibrary_msdos
| website = archive.org
| access-date = 2016-03-02
}}</ref>

Link https://archive.org/search.php?query=collection%253Asoftwarelibrary_msdos&page=1 (no results)
Label "collection%3Asoftwarelibrary_msdos"