When moving a user talk page to another title in the user talk namespace, the subpages are moved into the Project: namespace.
Version: 1.13.x
Severity: major
URL: http://test.wikipedia.org/w/index.php?title=Special%3ALog&type=move&user=Mr.Z-man&limit=3
Fixed in r35870.
The previous code used "an atrocious hack" to bump subject & talk pages to the appropriate target namespace, which sent you to the wrong place if you were directly moving a talk page to begin with -- adding 1 to the talk namespace instead of to the base subject namespace.
New code is nice and explicit and picks the right one.