[horde] Weird intermittent login failure

[Mark Hennessy]

Hi, I have a horde (3.1.3) setup with IMP (4.1.3) and a couple of other horde
apps, and I'm seeing a weird problem.
The horde is authenticating against a Courier IMAP setup running under
cPanel.

I open the browser and connect to the site running horde.  I log in with the
proper username and password.  Sometimes the problem shows like this:

I see the horde frame populate to the left and the "last login" bubble, but I
get a login prompt again.  I log in one more time at that prompt, and the
problem doesn't repeat.

Other times, it shows like this:
I log in, and I get to the inbox with the horde frame to the left, and click
on "New Message" or to view another folder, and I get a login prompt again.
I log in one more time at that prompt, and the problem doesn't repeat.

The problem only seems to happen the first time opening up the web browser
and logging in.  If the browser stays open after the second login the problem
doesn't happen again.  In the logs, when the login fails, I see IMAP login
failures in those instances.  Unfortunately, coincidence being what it is,
I'm having a hard time pinning down the origin of the problem.
I enabled PEAR_LOG_DEBUG, but I don't see any failures beyond the IMAP login
failures in the horde log.

More info:
horde 3.1.3 running with MySQL session management enabled, authentication
using IMAP through horde directly (not transferred to IMP for authentication)

Any advice on what to look at next would be greatly appreciated.
Thanks!

--
 Mark Hennessy