Articles marked as read without reading them

[Jon Ericson <Jon.Ericson@jpl.nasa.gov>]

I've got a group with lots of unread messages (so I can remember to do
something about them once I've read them).  Sometimes I only want to
see, say, the last 10 messages.  So from the *Group* buffer I do a
M-10 RET to enter the group.  Then I read the messages I'm interested
in and quit the *Summary* buffer by hitting `q'.  I haven't noticed
anything wrong with this until today when suddenly a bunch of old
messages, that didn't get displayed in the *Summary* buffer, were
marked as read.  I can't, unfortunately, reproduce this behavior
though. :( Does anyone know what might be causing this, where I can
look in the code, or can tell me what I'm doing wrong?

Thanks,
Jon
-- 
  But if serving the LORD seems undesirable to you, then choose for
  yourselves this day whom you will serve . . . But as for me and my
  household, we will serve the LORD.
  -- Joshua 24:15 (NIV)