When linking a question via HTTPS, the question doesn't appear in the Linked Questions sidebar.
In the question My avatar automatically changed, this was the initial screenshot:
So then the question was edited to use HTTP in the link instead of HTTPS:
After that, the question is now shown in the Linked Questions sidebar:
I've also repro'ed this in a comment on this post: Meta is... Japanese?. So if you use HTTPS in the URL, it doesn't link the posts. However, if you use HTTP instead of HTTPS, it works. Can this please be fixed?