[Pkg-exim4-users] save, in a user filter, is not a significant command

[Regid Ichira]

  Consider the following user filter:

    $ cat .forward
    # exim filter
    
    if $h_subject: is "exim filter bug"
    then
      testprint "$h_subject printed by is operator"
      seen save bug
    endif
    deliver jc at rome.example
    $ 

  Here, without the seen modifier, a message with the right subject
will be saved, and also sent to jc at rome.example.  Is that expected with
the out of the box configuration?