is this a bug 2.8.0 with \turn ?

[Jay Hamilton, Sound and Silence]

In the pdf from the code below measure 16 with the turn 
- the turn seems to have durational value throwing the 
rest of the piece off.
Perhaps there is something I do not understand about 
current practise with turns but this seems wrong and I 
can't find a way to fix it.
Thanks
Jay


\version "2.8.0"
\header {
  title = "Prelude"

  composer = "Frederic Chopin, op. 28 #4"

  copyright = "for study purposes only"
}

upper = \relative c' {
\clef treble
\key g \major
\time 2/2
\partial 4
b8.\p (b'16_\markup {"espressivo"}
b2. c4 b2. c4 b2. c4 b2. bes4 a2. b4 a2. b4 a2. b8. a16
a2.) gis4\> ~ gis\!  a8\< (b\!\> d
c e, a\! fis2.) a4 (fis2.) \acciaccatura b8 (a4
g8 fis c->\< b dis fis \times 2/3 {d' c b\!)}
b2. (c4 b2. c4 b2. c4.
b8.\< ais16 ais4\turn g'\!\> fis8. e16\! e8\f dis c'\> 
dis, dis e g b,
d c e e, a fis4.\!_\markup {"dim."} a8 fis2.)\p 
\acciaccatura b8 (a4 fis2.~ fis8.\< e16 e2.\!
fis4_\markup {"smorz. - - - - -"}e2. fis4 e2) r2\fermata 
<e, fis b e>2\pp
(<dis fis b dis> <e g b e>1\fermata)



\bar "||"
}

lower = \relative c' {
\clef treble
\key g \major
\time 2/2



}

\score {
        \context PianoStaff
        <<
        \context Staff = upper \upper
        \context Staff = lower \lower
        >>
        \layout { }
        \midi { \tempo 4=60 }
}


--
Childhood is a Journey not a race- Emma Sadinsky aged 8
Jay Hamilton
Sound and Silence
206-328-7694
www.soundand.com