Wrong articles on RET

[Rasmus <rasmus@gmx.us>]

Hi list,

I upgraded to the newest offlineimap, which required some changes
in my offlineimap rc file.  Following this, offlineimap decided
to re-syncronize all messages, perhaps due to a new, needed name
translation function.  Unfortunately, Gnus is now frustrated.

I handle all of my mail accounts in Gnus.  For mail groups I
display the 60 most recent mails when I click RET on one of them.
This used to work out absolutely brilliantly, with the most
recent thread/mail on top.  It still works as I'd like it to when
I open all messages [C-u {large number} RET] (i.e. most recent
on top with `threating').
But when I just click RET on a group a (to me) random (but
consistent) selection of mails is shown, typically several month
old (all from March/April, it seems).  I don't understand why
Gnus now want to show me these messages. . .  When I open 
webinterfaces the messages are still displayed in the correct order.

Does anyone know how I could solve this issue of Gnus showing the
`wrong' messages when I select a group?

Thanks in advance,
Rasmus