broken gnus-summary-refer-thread ? in gnus v5.13

[Gijs Hillenius]

Hi

Emacs-snapshot (GNU Emacs 24.1.50.1, 2012-06-22) comes with Gnus
v5.13. I mark a few mail boxes with # and hit G G to do a search in
these boxes for 'foobar'.

Then, I find myself in a buffer called 

*Article nnir:((query . "foobar") (unique-id . "12345.fsf"))*

with a handful of results.

Then, I go put the point at the message that I want, and hit 'A T'
(gnus-summary-refer-thread). I expected to be transported to the
'original mailbox' so I could mark the message (with !). But it seems
nothing happens.

*Messages says:

Fetching headers for nnir:((query . "foobar") (unique-id . 54321.fsf"))...done

If I mark the message in the nnir buffer, the tick mark is lost when
leaving the nnir buffer.

What did I do wrong?