Disappearing beams

[Oleg Eterevsky]

Hi!

After processing the attached file t5.ly by lilypond 2.0.1 (cygwin) all the 
beams in the first of two measures are visible and in the second are invisible. 
I also attach the resulting pdf file.

Best wishes,
Oleg Eterevsky.

\version "2.0.1"

upper = \notes \relative a' {
  \time 5/4
  \key ees\minor
  a8(  bes) a-. aes-. ges4-. bes,4( \grace {ces16[ c16]} des4)-. |
  ees2. f16( ges f ees  des4) |
}

lower = \notes {
  \time 5/4
  \key ees\minor
  ees,8( <bes, ges>4-.) ees,8( <bes, ges>4-.) bes,4(  bes,,4)-. |
  ees,8.( <bes, ges>16 r8.) ees,16( <bes, ges>4)-. bes,4(  bes,,4)-. |
}

\score {
  \context PianoStaff <<
    \new Staff \upper
    \new Staff {
      \clef bass
      \lower
    }
  >>
  \paper { }
}

t5.pdf
Description: Adobe PDF document