I recently noticed that duplicate banners (on math.SE, at least) do not update when the target question's title has changed. The specific example I came across was this question, that was closed as a duplicate of this question (screenshots below).
Shouldn't we be using a magically self-titling hyperlink for duplicate banners?
(Of course, if the only way of getting the indicated title to change was with an edit, causing the closed question to bump, then I would be totally fine with not having the duplicate banner update).
Something to mention is that on MathJax-enabled sites like math.SE, the duplicate banner is implemented differently; maybe that causes difficulty with the magic.
Code for duplicate banner:
Current title of the target question: