problem with "extra" lyrics appearing only sometimes

[Kieren MacMillan]

Hello all,

Apologies in advance: I don’t have time for a minimal example…
I’m supposed to have sent this engraving off this morning.  =\
I just need to figure out what’s wrong and move on.

I have the following structure:

      \new ChoirStaff <<
        \new Staff = "Staff_SA" \new Voice = "Voice_SA" << \global \SA_notes >>
            \new Lyrics \with { alignAboveContext = "Staff_SA" } \lyricsto 
"Voice_S" \S_words
            \new Lyrics \lyricsto "Voice_SA" { \SA_words }
        \new Staff = "Staff_TB" \new Voice = "Voice_TB" << \global \TB_notes >>
            \new Lyrics \with { alignAboveContext = "Staff_TB" } \lyricsto 
"Voice_T" \T_words
            \new Lyrics \lyricsto "Voice_TB" { \TB_words }
      >>

This allows me to have up to four lines of lyrics: one above and one below each 
of the two choral staves.

For some reason, some lyrics are appearing and others are not. It seems almost 
random. In my note code, where I want to have (e.g.,) some soprano words 
appear, I use:

    <<
      { \voiceTwo r2 a'8 gs' fs' e' ~ 2 ~ 2 }
      \context Voice = "Voice_S" { \voiceOne e''8 ds'' cs'' b' ~ 1 ~ 2 }
    >> \oneVoice r4   | % SA 25

As I said, this appears to work exactly as expected in many circumstances, and 
fail completely in others.
Any thoughts on what might be causing this intermittency?

Thanks,
Kieren.
________________________________

Kieren MacMillan, composer
‣ website: www.kierenmacmillan.info
‣ email: address@hidden