Try to parse (using Zend_Mail_Protocol_Imap::_decodeLine() ) the following line "* STATUS blurdybloop (MESSAGES 231 UNSEEN 0)", in the result you'll miss last "0" token. It's because of incorrect parsing of tokens in the following code fragment (file Zend/Mail/Protocol/Imap.php)

                // only add if token had more than just closing braces
                if ($token) {
                    $tokens[] = $token;
                }

In input line above last token is "0" but expression "if ($token) {" treat it as numeric 0 and hence as a FALSE value. So instead of adding string "0" code ignores it.