Erratic behaviour with Ties and LyricExtenders

[Daniel Johnson]

I've been having problems with LyricExtenders under Ties on 2.10.11. The 
attached example shows one of the LyricExtenders not extending far 
enough. This in fact is a fragment of a larger piece, and in the context 
of the larger piece none of the LyricExtenders extends further than a 
couple millimeters.

%%% BEGIN LILYPOND CODE %%%
\version "2.10.11"

\paper { indent = 0 ragged-right = ##t tagline = ""}

trbVox = {
\clef treble \time 6/8 \key f \major \autoBeamOff
<bes' e''>2. ~ | <bes' e''>2. | <a' f''>2. ~ | <a' f''>2. ~ | <a' f''>4 
r8 r4 r8 |
}
trbText = \lyricmode { al __ cor __ }

basVox = {
\clef bass \time 6/8 \key f \major \autoBeamOff
r8 e[-. d-.] c-.[ g-.] f-. | e[ d'] c' bes[ a] g | f2. ~ | f2. ~ | f4 r8 
r4 r8 |
}
basText = \lyricmode { l’eb -- brez -- za scen -- da scen -- da~al cor __ }

\score {
<<
\new ChoirStaff
<<
\new Staff = trbVoxStaff { \context Voice = trbVoice { \trbVox } }
\new Lyrics = trbLyrics { s2. }
\new Staff = basVoxStaff { \context Voice = basVoice { \basVox } }
>>
\context Lyrics = trbLyrics \lyricsto trbVoice \trbText
\lyricsto basVoice \new Lyrics \basText
>>
}
%%% END LILYPOND CODE %%%