\afterGrace \glissando draws incorrect line?

[steve]

 Howdy!

          I have a problem getting lilypond to draw the correct glissando
line...

        Here is  a pdf and lilypond source file

        http://gooeytar.com/projects/test/test.pdf
        http://gooeytar.com/projects/test/test.ly

      and another attempt

        http://gooeytar.com/projects/test/test2.pdf
        http://gooeytar.com/projects/test/test2.ly

        I want the glissando line to go from   fis - > a  and from dis -> fis

        but instead of dis -> fis I get a-> fis ???

           Ideas?

        here is a sample lilypond source

\version "2.18.0"

global = {
  \time 3/4
  \key e \major
  \clef "G_8"
}

 voiceone = \relative c' {
    a''4 < b,, dis a > dis16 a fis' dis |
    a'4 < dis,, a' b > a'16 fis b( a) |
    dis4 < fis, a dis >
    <<
      \new Voice \voiceOne { \afterGrace fis4 \glissando a8 }
      \new Voice \voiceTwo { \stemUp a4 }
      \new Voice \voiceThree { \afterGrace dis4 \glissando fis8 }
    >>
    < a, fis' >4 < gis e' >
 }

 voicetwo = \relative c {
    r4 < b dis > r |
    r4 b b |
    r4 b b |
    e,2
 }

  guitar = << \voiceone \\ \voicetwo >>

    \score {
        \new Staff { << \global \guitar >> }
        \layout { }
   }