Rendering bug in Lilypond 2.8.0 / 2.9.4

[Alain-Pierre P .]

Hello to all debuggers out there.

If you try to compile this little lilypond file with either lilypond 2.8.0 or
lilypond 2.9.4 :

% Start here
\version "2.7.40"

pianoG = \notemode {
  \key d \major
  \time 3/4
  \clef treble
  \acciaccatura a''8 b''4 a''8 \acciaccatura a''8 b''4 a''8 |
}

pianoF = \notemode {
  \key d \major
  \time 3/4
  \clef bass
  b,4. fis |
}

\score {
  \context PianoStaff <<
    \context Staff = upper \pianoG
    \context Staff = lower \pianoF >>
  \layout {
    ragged-last = ##t
  }
}
% End here

...you will find that the first accaciatura is stranglely rendered. If you cut
the "\acciaccatura a''8" and recompile the file, then the rendering is correct.

Alain-Pierre