Bug in MIDI generation

[Sebastiano Vigna]

In the following fragment from Scarlatti's K519 lilypond generates bad
MIDI output--it goes out of sync after the acciaccatura (taking away the
acciaccature makes it work):


mordb = \relative c' { g''8\prall ~ g16 f g aes32 bes }
mordupperb = \relative c' { g''4. ~ g ~ g \mordb }
mordlowerb = \relative c { \clef violin des''8 bes g \clef bass  e des bes  g e 
des  <c, c'>4. }

\score {
        \context PianoStaff <<
           \time 3/8
           \context Staff = upper {
           \set Staff.midiInstrument = "harpsichord"
           \key f \minor
           \relative c' {
              
              \mordupperb \acciaccatura aes8 \mordupperb

           }  
           }

           \context Staff = lower {
           \set Staff.midiInstrument = "harpsichord"
           \key f \minor
           \relative c {
               \mordlowerb\mordlowerb

           }
           }
        >>

        \midi { \tempo8=300 }
}


-- 
Ciao,

                                        seba