midi plays tied notes

[Richard Froese]

Hello,

In the following fragment the last tied A flat in the top voice
is played by midi. It works fine if I leave out the bottom voice, or
take away the first bar. It also worked under 2.0. (I just upgraded to
2.2.) Can anyone help me with this? 

-----------------------------------------------------------

upperNotes = \notes{
                <<
                \relative e'''{
                        es4. bes4. a4 as8 ~ as4. ~ 
                        as4. ~ as4.
                }\\
                \relative d''{
                        d4 g8 ~ g4 c,8 ~ c4 cis8 ~ cis4. 
                        e4 f,8 des'4 c8 ~ c4.
                }
                >>
}

\score{
        \new Staff {
        <<
                \time 12/8
                \clef violin
                \upperNotes     
        >>
        }
        \midi {\tempo 4 . = 140}
        \paper{}
}

-------------------------------------------------------------------
-- 
Richard Froese <address@hidden>