[Norton AntiSpam] header appears twice

Norton Internet Security 2012. Program scans for spam, and inserts a header “[Norton AntiSpam]” into the subject line of every message it determines to be spam. Unfortunately it inserts that header twice so the subject line looks like: [Norton AntiSpam][Norton AntiSpam]old subject This makes the old subject hard to read since it’s scrolled off to the right. Any ideas for fixes? Thanks.