Use the VisualEditor to edit an article on mediawiki.org, enter the word "bugzilla" and turn it into a link (highlight, Ctrl-K). The link input widget proposes a list of link targets, starting with "bugzilla" (checked), "Bugzilla/Notes/4198" and "Bugzilla". Click on the third one ("Bugzilla"). With quick eyes, you will notice that "Bugzilla/Notes/4198" is checked instead, but the list disappears immediately and the target box contains the string "Bugzilla". It appears as if the desired "Bugzilla" had been accepted as link target. Close the link input widget and preview your changes: "Bugzilla/Notes/4198" is used as link target.

Another instance:

Go to https://en.wikipedia.org/wiki/War?veaction=edit and turn the word "integral" in the second paragraph into a link. The link input widget proposes a list of link targets, starting with "integral" (checked), "Integral domain" and "Integral". Click on the third one ("Integral"). With quick eyes, you will notice that "Integral domain" is checked instead, but the list disappears immediately. It then appears as if the desired "Integral" had been accepted as link target. Close the link input widget and preview your changes: "Integral domain" is used as link target.

It's likely that these cases won't be reproducible for long since the suggested target list is highly dependent on the respective wiki's current set of articles.

Version: unspecified
Severity: major