Problem with partcombine and shape notes

[Bumby Hymnal]

I've run into a problem with using \partcombine while using \aikenHeads.  The problem is that under certain circumstances the aiken shape note heads are not used in the output of \partcombine.  The strange thing is that it sometimes works.  The following snippet shows 4 different voices.  The first voice is a basic scale.  The 2nd voice is exactly the same.  The third voice is a third below the first voice, and the fourth voice alternates between being unison and being a 3rd apart from the first voice.  Each voice is rendered independently and shows the shape notes properly.  Then the first voice is combined with the 2nd (identical), then the 3rd (down a 3rd), and the 4th (alternating unison then a third).  The first two cases render the shape notes properly.  The last case of with alternating unison / 3rds produces proper shape notes when unison, but normal (non shape) notes when rendered as a chord.

 

SNIPPET:

 

\version "2.19.49"

 

firstVoice  = \relative c' { \aikenHeads c4 d e f g a b c }

sameVoice   = \relative c' { \aikenHeads c4 d e f g a b c }

thirdVoice  = \relative c' { \aikenHeads a4 b c d e f g a } fourthVoice = \relative c' { \aikenHeads c4 b e d g f b a }

 

<< 

  \new Staff \with { instrumentName = "firstVoice"  } \firstVoice

  \new Staff \with { instrumentName = "sameVoice"   } \sameVoice

  \new Staff \with { instrumentName = "thirdVoice"  } \thirdVoice

  \new Staff \with { instrumentName = "fourthVoice" } \fourthVoice

  \new Staff \with { instrumentName = "unison"      } \partcombine #'(2 . 12) \firstVoice \sameVoice

  \new Staff \with { instrumentName = "thirds"      } \partcombine #'(2 . 12) \firstVoice \thirdVoice

  \new Staff \with { instrumentName = "mix"         } \partcombine #'(2 . 12) \firstVoice \fourthVoice

>> 

partcombine_issue.ly
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partcombine_issue.png
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