Related to Are old links updated automatically?, If a question links to another question on BasicallyMoney.com, those questions do not show up on the linked sidebar.
We can't reproduce this. As you can see on this very post, the post you linked shows up.
Oh, I see -- I replaced all instances of
http://money.stackexchange.com for now.
As posts are edited and links are updated naturally over time (this happens on page load a small percent of the time) this should fix itself.