I also had the following strange behavior, using it with GWT:
in my html page I set the pie behavior.
Just when my gwt stuff is loaded I do wrap a piece o html page in a new html div element. This html snippet that was being wrapped contains pie stuff. After wrapping, the page got very ugly. I noticed many css3 html elements before the div element that was wrapped by pie then normally.
So some how the dom de-atcchement and attachment action triggered pie to do something which wasn't correct.
After I remove the wrapping, it also looked ok again (also the inserted css3 tags).
What I did in gwt: add a div element just before the div element I want to wrap and added this to this new element.
It took me a while to find out what was going wrong as I have it working on other places.
It was difficult for me to put it somewhere so you can see it. As such I have some screenshots, maybe that helps.
Ie error (with wrapping): http://sub.ited.nl/pie/error.pnghttp://sub.ited.nl/pie/errorIe.png
Ie ok (witout wrapping):http://sub.ited.nl/pie/ok.pnghttp://sub.ited.nl/pie/okIe.png
If anybody is interested, let me know. I see if I can drop it somewhere