http://meta.stackexchange.com/questions/99672/community-Community ♦ should discriminate more when bumping unanswered questions♦-should-discriminate-more-when-bumping-unanswered-questions
well, you can see there. The diamond (and other problematic Unicode characters) in the title breaks the automatic prettification of internal question links.
This becomes a bit more of an issue when one wants to link to an answer. For example http://meta.stackexchange.com/questions/242571/diamonds-Diamonds (♦) break the automatic hyperlink parser♦-break-the-automatic-hyperlink-parser/242572#242572 should link to Martijn's answer, but, it doesn't (tangent, but a different issue is that http://meta.stackexchange.com/a/242572/213963https://meta.stackexchange.com/a/242572/213963 which is the share link doesn't auto-prettify unless the userid part is removed - one keeps having to manually remove things to get the auto prettify to engage).
If one looks at the html generated for http://meta.stackexchange.com/questions/238644/Users who can't write good posts ≠ users who want to write good posts for the title and the url linked in the
<h1> of the page, we get:
<title>Users who can't write good posts ≠ users who want to write good posts - Meta Stack Exchange</title>
<h1 itemprop="name"> <a href="/questions/238644/users-who-cant-write-good-posts-%e2%89%a0-users-who-want-to-write-good-posts" class="question-hyperlink">Users who can't write good posts ≠ users who want to write good posts</a> </h1>
And while that's a long link title, I will point out that the quote as part of the word "can't" was removed from the slug. The bug is that this should be done for other characters too.