midiExpression in voices with Staff_performer

[Leo Correia de Verdier]

Dear list!

I’m trying to add different midiExpressions to a staff with two voices on 
different midi channels. The problem I have is that \set midiExpression only 
seems to work if placed before the first note of a voice. Subsequent \set-s 
don’t appear in the output midi file. The following \set midiExpression works 
as long as Staff_performer is in its original place in the staff context, but I 
can’t get it to work with it moved to Voice. I still think it is something I’m 
doing wrong, but it might be a bug.

\version "2.19.82"
\score {
  \new Staff <<
    \new Voice \relative c''' {
      \set midiExpression = #.1
      \voiceOne
      g1 
      \set midiExpression = #.4 %this doesn't make it to the output midi file
      e 
    }
    \new Voice \relative c'' {
      \voiceTwo
      b1 c
    }
  >>
  \layout { }
  \midi {
    \context {
      \Staff
      \remove "Staff_performer"
    }
    \context {
      \Voice
      \consists "Staff_performer"
    }
  }
}