MIDI output for appoggiaturas not always correct

[Ralph D . Jeffords]

> I'm not top posting.
%----------------------------------------------------
% Midi output for \appoggiatura is not timed properly 
% in articulated mode. Same bug appears in Ver 2.19.16
%----------------------------------------------------
\include "articulate.ly"
\version "2.18.2"
\score {
  \new PianoStaff <<
\articulate 
\new Staff = "upper" 
\relative c' {
  \clef  bass
  \key c \major
  \time 2/4
%-----------------------------------------------
% incorrect timing: in third appogiatura the d32
% is longer than a 32nd note
%-----------------------------------------------
  \appoggiatura f,32 d'8   \appoggiatura e,32 e'8 
        
        \appoggiatura d,32 f'4 |

%------------------------------------------ 
% correct timing when expanded out by hand
%------------------------------------------
    f,32 d'16.              e,32 e'16. 
        
          d,32 f'8..            
  } %relative   
\new Staff = "lower"
%-------------------------------------------
% Rhythm part for reference of beats
%--------------------------------------------           
\relative c' {
  \clef  treble
  \key c \major
  \time 2/4
    c'8 c  c c | c c c c
  } %relative
>> 
\layout { }
\midi { }
}%score -----------------