Openfire 4.0.2 + Pandion 2.5 = Error 500 adding contact intermittently?

We’ve recently upgraded our Openfire to 4.0.2.

Though all other IM Clients appear to be working fine, even Pandion 2.6; Pandion 2.5, which our user base is glued to, encounters errors adding contacts.

At first it was thought to be packet filter rules causing the error, but we’ve since discovered that error 500 when adding a contact is intermittent, and with some prelim research, seems the IM Client is interpreting a wait command as an internal server error.

By re-attempting to add the same contact multiple times, average of 6 attempts, it succeeds. We’d really like to know what causes this. Advising this volume of users to perform the workaround of re-attempting many times does not reflect well on the products or our services.

Gut reaction of any IT personnel would be - Upgrade the clients, get the users with the times, … but I’m sure you can appreciate that Orgs get stuck in their ways, and its not ours to question why.

Any info or ideas for troubleshooting, gathering tech details, etc, we’d be very open to. Hoping to dig to the bottom of this quickly and benefit the community & product along the way.