30s delay propagating messages

I have an OpenFire server running with either an embedded DB or SQLServer 2008 R2. When I initiate a conversations between two bots there are delays of almost exactly 30s between the time that the message is sent by one side and received by the other. These delays do not show up on every machine. Single CPU machines (i.e. VMs) produce the delays reliably so it looks like a thread timing issue.

I looks like a bug in OpenFire but I can’t find any similar reports on the Internet.

I am stumped. Does anyone have any suggestions?