HN rewrites headline text by default, but if you edit and save afterwards it doesn't rewrite the second version. Maybe the same is true of the URL text?
Unfortunately normal users can’t edit the url after submitting.
Yeah HN does that, screws up reddit comment links too.
It’s one of the most annoying features of HN. I’ve tried submitting GitHub comments to no avail, since it’s impossible to get a permalink to them.
I guess you could create redirect page redirecting to specific comment and submit that?