Interesting...I've seen this on my '03. A few years back, if I recall correctly, I may have seen a tip regarding a fix - which I may have tried (don't recall exactly what is was) but the problem went away. It occurred again more recently and, after reading it wasn't something about which I should be concerned, I did my best to ignore it. It has since gone away and reappeared a few times, Most recently, it's been gone for several days. I say don't lose any sleep over it!