Strange Message Dropping Problem

I have been having some strange instant message problems that I'm 
wondering if anyone else has experienced.

Sometimes Exodus will not display an inbound instant message.  I have 
only seen the problem with Messages, not Chat.

I opened up a debug window to help test the problem, and I see the 
messages coming through, but they just don't get displayed by Exodus.

The odd thing is that messages from certain people do get through.

In a bug I filed it was mentioned that I'm probably blocking that 
person, but I've never blocked anyone and my blocked list is empty in 
the preferences.

When I first noticed the problem, I would not receive messages from a 
person whom I had a chat window open with.  But now it seems I don't get 
messages from other people without having a chat window open - so 
perhaps the chat window has nothing to do with it.

Is there somewhere else I can look to help further debug this problem?

I am using Exodus 0.9.0.32 and 0.9.0.15 in the tests.

Thanks,

Jeff