folding mode broken

I have recently started using folding `folding-version' is a variable declared in Lisp. -- loaded from "folding" Value: "1.11" Documentation: Version number of folding.el. I am using xemacs-21.4.10. I open a file. The file has // Local Variables: // eval: (folding-mode nil t) // End: I am asked whether to do the eval and answer y. Now I am at the top of the file. I hit C-s and start searching. Hit C-s a few more times. After several times, the file is modified! That's really annoying, especially since when I try to undo the change, I'm then told the change is in a part that is invisible. I have to go back to unfolding the whole buffer, and then undo the change (which is just a whitespace difference).