\version "2.14.2"

music =  \relative c {
  \set stringTunings = #guitar-open-d-tuning
  % comment \voiceTwo and the output is good
  \voiceTwo
  g4 \acciaccatura g8 f4 d \acciaccatura { f16[ f] } f4
  
}

\score {
  \new StaffGroup <<
    \new Staff <<
      \context Voice { \clef "G_8" \music }
    >>
    \new TabStaff  <<
      \context TabVoice { \clef "moderntab" \music }
    >>
  >>
}