My Gerrit-jitsu isn’t good enough for figuring out when it broke, but it is good enough to figure out that this code had looked like basically this since 2005 and initially worked the same for both links, both user and user talk:
https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/core/+blame/ffe4025ef6e1ccdfe00dbbe2a6ccdca003f183d0/includes/SkinTemplate.php

$personal_urls['userpage'] = array(
    'text' => $this->username,
    'href' => &$this->userpageUrlDetails['href'],
    'class' => $this->userpageUrlDetails['exists']?false:'new',
    'active' => ( $this->userpageUrlDetails['href'] == $pageurl )
);
$usertalkUrlDetails = $this->makeTalkUrlDetails($this->userpage);
$personal_urls['mytalk'] = array(
    'text' => wfMsg('mytalk'),
    'href' => &$usertalkUrlDetails['href'],
    'class' => $usertalkUrlDetails['exists']?false:'new',
    'active' => ( $usertalkUrlDetails['href'] == $pageurl )
);

So whatever broke in the handling of both links (and it was broken, otherwise you wouldn’t have had to reset the link colour of red links to blue in Vector 2022, right?) has probably zero thought about it, and is much more likely to be an oversight either during rewrite of the skin system or somewhere else. Assigning .new to the list item instead of the link doesn’t scream intentional.

Could we do a git bisect and work out when exactly this broke (either accidentally or intentionally)?

Change #1306415 had a related patch set uploaded (by Neriah; author: Neriah):

[mediawiki/core@master] Render missing user talk page links as redlinks

https://gerrit.wikimedia.org/r/1306415

Actually, not just Vector(s), same thing happening for https://en.wikipedia.org/wiki/Main_Page?useskin=monobook
If there’s a skin-agnostic skin issues tag, maybe needs a change to that. I guess that makes tracking down the issue simpler, though.

Exact same thing happening in new Vector, too (also .new on <li> instead of <a>):

Change #1248681 abandoned by Mounil2005:

[mediawiki/skins/Vector@master] T419012: Fix temporary account icon not flipped in RTL in Vector 2010

Reason:

As Job Robson said:
Ut seems minor and hopefully will never impact WMF production.

Changed ended up being intentional. Closing.

This probably has something to do with T399175.

Change #1203501 abandoned by A smart kitten:

[mediawiki/core@master] [DNM] Proof of concept - patch to mw/core to allow notification icons to be shown on legacy skins for temporary accounts

Reason:

patch is merge-conflicting; seems like this might've happened (at least, for some skins) in another way anyway: https://phabricator.wikimedia.org/T409777#11655682

https://gerrit.wikimedia.org/r/1203501

In T425305#11885604, @A_smart_kitten wrote:

FWICS, this seems like a report that the part of the map highlighted in the screenshot below is causing a horizontal scrollbar to appear (please correct me if I'm wrong, @Neumarcx). I can reproduce this myself, and deleting this HTML element appears to result in there no longer being any (or as much) horizontal overflow. However, I'm not sure (and not familiar enough with on-wiki maps to know) whether this would be caused by something on dewiki, or by something in the software.

FWICS, this seems like a report that the part of the map highlighted in the screenshot below is causing a horizontal scrollbar to appear (please correct me if I'm wrong, @Neumarcx). I can reproduce this myself, and deleting this HTML element appears to result in there no longer being any (or as much) horizontal overflow. However, I'm not sure (and not familiar enough with on-wiki maps to know) whether this would be caused by something on dewiki, or by something in the software.

Tested & verified fixed. You might have to purge the cache in some cases, but most pages shouldn't need this.

Should be fixed when wmf.23 rolls out tomorrow (Apr 9).

In T418220#11797134, @Jdlrobson-WMF wrote:

I see this is marked as "Done" but not resolved. Anything left?

We often make changes to menus to support Vector 2022 and Minerva. Given the approach taken in the patch (https://gerrit.wikimedia.org/r/c/mediawiki/skins/Vector/+/1243072/7/includes/SkinVectorLegacy.php) the order cannot be guaranteed as stable.

Mentioned in SAL (#wikimedia-operations) [2026-04-07T21:17:54Z] <cscott@deploy1003> Finished scap sync-world: Backport for [[gerrit:1268600|Ensure RevisionOutputCache uses post-processing options where appropriate (T421629)]], [[gerrit:1268625|Remove Navigation Menu Link Instrumentation on Personal Dashboard (T422512)]], [[gerrit:1268633|ForeignWikiRequest: Pass session to internal 'centralauthtoken' request (T422218)]], [[gerrit:1268651|PHP SDK: Handle experiment config missing or

Mentioned in SAL (#wikimedia-operations) [2026-04-07T21:10:51Z] <cscott@deploy1003> cscott, kgraessle, sfaci, matmarex: Backport for [[gerrit:1268600|Ensure RevisionOutputCache uses post-processing options where appropriate (T421629)]], [[gerrit:1268625|Remove Navigation Menu Link Instrumentation on Personal Dashboard (T422512)]], [[gerrit:1268633|ForeignWikiRequest: Pass session to internal 'centralauthtoken' request (T422218)]], [[gerrit:1268651|PHP SDK: Handle experiment config

Mentioned in SAL (#wikimedia-operations) [2026-04-07T21:09:01Z] <cscott@deploy1003> Started scap sync-world: Backport for [[gerrit:1268600|Ensure RevisionOutputCache uses post-processing options where appropriate (T421629)]], [[gerrit:1268625|Remove Navigation Menu Link Instrumentation on Personal Dashboard (T422512)]], [[gerrit:1268633|ForeignWikiRequest: Pass session to internal 'centralauthtoken' request (T422218)]], [[gerrit:1268651|PHP SDK: Handle experiment config missing or

Change #1268600 merged by jenkins-bot:

[mediawiki/core@wmf/1.46.0-wmf.22] Ensure RevisionOutputCache uses post-processing options where appropriate

https://gerrit.wikimedia.org/r/1268600