dot and stem problems

[Robert Garrigos]

I have this code:

\score {
  <<
    \new PianoStaff
    <<
      \new Staff = "upper" \relative c' {
        \key bf \major
        \time 6/8
        | <d f>16 c <d f> c <d f> c <d f> c <d f> c <d f> c
        | <d f> c <d f> c <d f> c \stemDown <d f> c <d f> c <d f> c
        | <<
          { s2. |<d f>4. <bf d>\fermata }
          \\
          { <d f>16 c <d f> c <d f> c <d f> c <d f> c <d f> c~ | c4. s4. }
        >>
      }
      \new Staff = "lower" \relative c' {
        \key bf \major
        \time 6/8
        \clef bass
        | <<
          { r4^\markup {\italic dolcissimo} r8 <f,, d'>4.( | <c' f> <d 
bf'>4)\once \shape #'((1 . 1.5) (0.5 . 1.5) (0 . 0) (0 . 0))(\change Staff = 
"upper" f''8)^\markup {\raise #2 \italic "m.e"}(| c4. g'4 f8 | d'2.\fermata) }
          \\
          { <bf,,,, f'>2.~ | <bf f'>~ | <bf f'>~ | <bf f'>4. <bf f' bf>\fermata}
          \\
          { s2. | s2. | s2. | s4. \crossStaff d'4.}
        >>
      }
    >>
  >>
  \layout {
    \context {
      \PianoStaff
      \consists "Span_stem_engraver"
    }
  }
}

which prints this:



Note the displaced dots and the connected stem with the high d note. How can I 
fix this?

Thanks.

Robert