It's just happened to me as well. The strange thing is that I received the first part of the notification in Italian (my language) and then, instead of the text of the message, the [[MediaWiki:Missing-article]] message, but in Norwegian, that is the language of the user posting the message. The provided link doesn't show anything, but the message exists: https://translatewiki.net/w/i.php?title=Thread:Template_talk:User_2500/Members_of_User_2500/reply_%282%29&oldid=3125215

TWN is using LQT 2.0-alpha r91397

Ciao Nemo bis,
questo messaggio ti è stato inviato da translatewiki.net per segnalarti che una nuova risposta a 'Members of User 2500' su Template talk:User 2500
è stata creato il 4 lug 2011 alle 17:44 da Nghtwlkr.

Puoi leggerlo a http://translatewiki.net/w/i.php?title=Template_talk:User_2500&offset=20110704154421&lqt_mustshow=15102#Members_of_User_2500_15102

Il testo è:
Databasen fant ikke teksten på siden som den burde ha funnet, med navnet «Thread:Template talk:User 2500/Members of User 2500/reply (2)» .

Dette skyldes vanligvis at man følger en utdatert diff- eller historikklenke til en side som har blitt slettet.

Om dette ikke er tilfellet kan du ha oppdaget en feil i programvaren.
Vennligst rapporter dette til en [[Special:ListUsers/sysop|administrator]], oppgi da nettadressen.

Clearly a improper use of new Article( $title ); some where.

Happened again with http://translatewiki.net/w/i.php?title=Template_talk:User_2500&offset=20110704184922&lqt_mustshow=15112#Members_of_User_2500_15112 (but this link works... no it doesn't work any longer), ie http://translatewiki.net/wiki/Thread:Template_talk:User_2500/Members_of_User_2500/reply_(5) .
The notification of a concurrent message (by Nike) worked.

Related/duplicate of bug 23503?

• Bug 29004 has been marked as a duplicate of this bug. ***

This is similar to, or even a duplicate of, Bug 30760

• Bug 30760 has been marked as a duplicate of this bug. ***

Does this still happen?

I haven't seen this recently.

(In reply to comment #8)

Does this still happen?

It's hard to check... Investigation based on comment 2 would probably be useful?

Yes it is hard to check. There are no steps to reproduce.

Indeed. Those who keep MediaWiki mail in their mailbox, please search for "Special:ListUsers/sysop" (the error can be in any language so it can't be used).
The last I found was in November 2011, but I had to empty my Thunderbird trash for a bug and my gmail mirror often sends them to spam, etc. etc.

(In reply to comment #12)

The last I found was in November 2011, but I had to empty my Thunderbird
trash
for a bug and my gmail mirror often sends them to spam, etc. etc.

Tentatively closing. There are some related changes that could have actually fixed this.