Duplicate list messages?

Is anyone else seeing duplicate messages every once in a while? I got two from Jay (about the IBM terminal) spaced 55 minutes apart but with otherwise identical content. I think there was a pair like this yesterday from someone, and two or three pairs last week. Looking at the headers of these latest two, there are differences in timing, and one of them references 'billy.ezwind.net' in connection with some Spam-Assassin lines, whereas the other doesn't. Yeah, I know this is really an off-list admin thing - I was just curious whether others had seen it happen too. (Jay, if it's useful and might be something happening at your end, I can try and save any more I see like this and see if there's any pattern to which ones it happens with... prod me off-list if needs be) cheers Jules