We have noticed a problem on our site related to cookie handling and the Firefox (version 19.0.2) and Chrome (version 25.0.1364.172 m) and the cookies generated by the EU cookie plugin required to meet EU regulations.
The problem, which is (we believe) caused by the use of the Joomla system (page) cache manifest itself either as no EU message being displayed, to enable acceptance of the cookie, or as the cookie acceptance appearing to be ignored (even though it has been accepted) and the message continuing to be displayed. Option changes to the system cache plugin do not make any difference.
Not a show stopper but a problem none the less. The problem although first noticed on our own site is also evident on other sites complying with the EU regulations and using cookies.