Users getting random user offline messages for online users

I am having a problem I did not see answered in any of the discussions after a few hours of searching.

What is happening is that online users, showing online in the Spark client, are randomly getting messages about users offlien during active conversations. I had this happen twice yesterday during troubleshooting. I was actively talking with the user that complained of the problem and the user that she was chatting to. Randomly I got error messages that the user was offline even as I watched the messages posting in the archive window. I restated openfire and still the problem persisted.

I do not see any messages in the server logs indicative of any problems and the users are getting the messages immediately even with the offline messges being sent from the server.

This server is very low usage, 8 users presently, without any disk space or system issues that I have seen at all.

What else can I start digging into to check? The users are not tech savy and not always available to spend hours diagnosing their machines.

Thanks!