Board Thread:Support Requests - Getting Technical/@comment-3218221-20170927182121

An anonymous user made their first edit to a page today, and when I went to thank them on their talk page (wanting to go beyond the standard welcome tool), I noticed that there was no welcome message as there ought to have been. You'll see that my thank-you is the only entry on the linked talk page. I recalled that this wasn't the first time in recent memory a welcome message had failed to appear, and searched for one of the newer logged-in users to check. This logged-in user, who first made an edit on Jan 6, 2017, has no talk page at all because no welcome-message was triggered. She also does not have a profle/user page, though the wiki has a basic creation tool for that.

Now, the welcome-tool has left messages for new users in the recent past. Here's a anonymous user's talk page sporting the welcome message, as applied for the user's first and only edit on September 8. And here's  a logged-in user with an older version of welcome-message-user on their talk page, triggered when they created their profile on June 21, 2016.

So - why are some users not receiving the welcome tool? Page-user, welcome-message-user and welcome-message-anon are all enabled. The welcome-user is set to @latest, not @disabled - @latest, as Help:Welcome tool says, @latest is the most recently active admin, aka me.

I had the idle thought that maybe @latest wasn't registering me as recently, only because I free-associated it with how Special:Community more often than not (which is the vast majority of the time) does not register me as a "top-contributor" - not that I care about rankings, the thing is - it doesn't list me even when no other users have made edits that week. (Yes, I've reported that to Staff more than once for the sake of technical concerns. It's been happening ever since Special:Community was introduced).

Even if that was the case (which may not even be possible, as far as I know), @latest is supposed to fall back on a Staff user as a signee when no admin is available - and besides, I don't see how that would have affected the tool's triggering.

What am I missing? 