The current implementation of HTMLDocument#jsxGet_cookie() returns an invalid cookie string:
Instead of encoding a cookie's value it just returns the value as double quoted string if it contains at least one whitespace which is quite incorrect in a real browser's point of view.
Affected source code: class HTMLDocument lines 647-653 HtmlUnit v2.8.
Now fixed in SVN. Thanks for reporting.
We previously were adding quotes in HTMLDocument#jsxGet_cookie() because we were incorrectly receiving cookies with quotes removed when set in a response header.