The emphasis in the PR title distinguishes this from #695 since the problem there appears to be that characters within the URLs were modified, causing a mid-URL color change.

But URLs appear to not be linked even if the URL as a whole was added (example), or even if they're just in comments alongside changes (example—note that I unfolded the top of the diff to get there, not sure if that matters). I'm pretty sure this is a regression.

URLs do appear to be linked if they're in non-PR code blocks (example).