Forward of email

Today I forward a message to a friend.  In the Subject box it displayed "Fwd:".  No other addresses were in the "To, CC or BCC".  I entered the address of one person, however, everyone,  20 people on the original email received the message again.  I have used Forward a lot and never had this issue.   I have checked my setting and can't find anything unusual.  Does anyone have a clue what happened?