Incorrect interpretation of grace notes in MIDI

[liang seng]

Hi, I discovered that sometimes grace notes aren't interpreted incorrectly 
in MIDI generated by Lilypond.  Here is an extract from the file:

\version "2.7.18"
global = { \key b \minor
\time 3/4 }
\score {
\relative
\new StaffGroup <<
<< \new Staff {
\set Staff.midiInstrument = "flute"
\global d'8.[\( \grace { e32[ d cis d] } e16]\) \grace eis4 fis4 fis g g g } 
>>
<< \new Staff {
\set Staff.midiInstrument = "violin"
\global fis,8 b d b fis b g b e b g b } >> >>
\midi { \tempo 4=60 }
\layout { }
}

Here, the MIDI interpreted the first grace note of the flute part 
incorrectly, resulting in the timing of the flute part being slowed by about 
half a beat. This is very apparent as when the 2nd bar is heard, the flute 
part is distinctly delayed and off-beat. There is no problem at all with the 
violin part MIDI. Is this a bug?
Thank you.

piece.midi
Description: audio/mid

piece.pdf
Description: Adobe PDF document