RFC 1036 (http://www.ietf.org/rfc/rfc1036.txt) says that the full name of person who sent the message is might contain in parentheses, after the electronic address in the "From" line. MTA Postfix adds the full name after e-mail in the "From" header. But RoundCube ignores the full name as a comment and display only e-mail.
You should create a ticket here: http://trac.roundcube.net/