The bug has been opened on https://bugs.launchpad.net/ubuntu/+source/evolution/+bug/104936

"Binary package hint: evolution

Trying to set up a "Search Folder" to identify emails that have been incorrectly tagged as Junk.

As near as I can determine, Evolution is hiding *all* Junk emails from *everything*, even if I set up a filter that explicitly tests for the "Junk" flag.

Mail store is on Cyrus IMAP 2.1.18-5ubuntu1, although it doesn't seem to matter whether the tagged email is on the IMAP server or in a local Evolution-managed mbox.

To replicate:

1. Tag an email as "Junk"
2. Configure a Search Folder to "Status is Junk"; specify source folder (I've defined both the actual folder the mail is in, and the "Junk" folder; I've also set it to "All available local and remote").
3. Check to see if the email shows up.
...
My specific purpose is to try and catch emails that are *definitely*
being tagged incorrectly as spam (eg: work-related emails, that I can't
afford to overlook). With a Search Folder, I have something that I can
use for a "quick'n'dirty" first-round check, to let me know I need to
tweak my spam filtering.

To this end, I'm trying to set up a Search Folder that would simply
display all emails tagged as Junk that match other criteria (eg: to/from
my work domain). I seem to recall this working in a prior release of
Evolution, but this is not a 'feature' I use often, so I can't remember
the specifics (I know it was before I switched to Ubuntu,
though--although it *was* an Evolution 2.x release).
...
>doesn't using a search on the junk directory would do the trick?
...
Nope; that was one of the first things I tried, which is why I figured
this was a bug (I remember that trick working in an older 2.x release of
Evolution, but I don't remember which one; I was also using
Mandrake/Mandriva at the time)."