Why do defunct links to the old astronomy site still format correctly into a linked title?

This question pointed out that there are still a number of links to posts on the old Astronomy SE site kicking around, and that they mostly redirect to new, unrelated questions and answers in the new Astronomy site. I feel those links should have been automatically edited at the time of the migration, but it doesn't really matter, since a quick query turns up ~30 or so sites, which can easily be edited manually.

I do find one thing pretty weird, though: when those links are posted as a raw URL, they still format correctly, for some reason. As an example, see this question, which until recently contained the explicit URL

https://astronomy.stackexchange.com/questions/861/why-did-the-asteroid-belt-between-mars-and-jupiter-form-as-it-did


which is a broken link (i.e. should point here) but nevertheless still formats correctly into a full title with the old link.

This feels weirdly buggy to me, though of course the real bug is that the URLs were not auto-updated to begin with.

• No repro, posting the raw link in a new answer does not format it. I think the post text was simply formatted into the correctly titled link once when the old astronomy.SE still existed and the post not edited since then.
– ACuriousMind Mod
Feb 22, 2017 at 13:56
• Indeed, it's no-repro on newly posted links, but consider e.g. this answer (with the explicit url in its revision history). (Don't edit it yet, though, or it reverts.) Feb 22, 2017 at 14:01
• Yeah, so this shows the source for a post is only parsed once per revision into what's displayed on the site, no?
– ACuriousMind Mod
Feb 22, 2017 at 14:04
• @ACuriousMind I don't claim to have uncovered a big mistery ;-), I just thought it was interesting enough. Feb 22, 2017 at 14:05