If I run a search which is no longer valid (i.e. uses old e-mail on one of the fields), Bugzie displays an error with 'forget' and 'edit' links. When I click the 'edit' link, a random part of the URL goes to 'keywords' field; my guess is mis-escaping.
Either fixed in Bugzilla 4.2 or I just can't reproduce it. If this issue is still persistent then please provide such a search url.