(Sorry for top-posting - my newsreader made me do it!)
Yes, that's a bug. Fixed in CVS. Thanks!
The next version will change the behavior of exists() somewhat. It should be less prone to misclassification.
By the way, I almost missed this message because it was posted as a reply rather than a new message. That caused my newsreader to thread it way down in the middle of another discussion. The only reason I saw it was because I was following that thread.
--Beman