bendAfter problems with polyphony (chords and partcombine)

[Matt Huber]

Hello~

I am having problems getting \bendAfter to function correctly when there are multiple notes on the staff.  It appears to me that during polyphony (either using the <c c> chord structure, or by using /partcombine) that when two notes share a stem, the drop created by /bendAfter is not printed.  There is no error in the log.  The following example demonstrates this:
-------------------------------------
\version "2.12.3"

\new Staff {
  \set Staff.instrumentName = #"Chord"
  \relative c''' {
    <g c>4 r2. |
    <g c>4-\bendAfter #-6 r2. |
  }
}

partA = \relative c'' { 
  b4-\bendAfter #-6 r2. |
}
partB = \relative c' { 
  e4-\bendAfter #-6 r2. |
}

<<
  \new Staff {
    \set Staff.instrumentName = #"A"
    \partA
  }
  \new Staff {
    \set Staff.instrumentName = #"B"
    \partB
  }
  \new Staff {
    \set Staff.instrumentName = #"A+B"
    \partcombine 
    { \partA }
    { \partB }
  }
  \new Staff {
    \set Staff.instrumentName = #"B+A"
    \partcombine 
    { \partB }
    { \partA }
  }
>>
-------------------------------------

For the "Chord" staff, I would expect to see two bends (one off each note) in the second measure.  This is how it is in the original score I'm scribing, at least.

It is interesting to me that both bends appear on the "B+A" staff (I had to zoom in the pdf to see them both as they overlap).  I think this is because the notes do not share a stem.

I did search the manual, the user-archive, and the snippets, but I don't see this issue having been addressed. Am I using /bendAfter incorrectly for polyphony, or is there something else going on that I'm not aware of?

Thanks!
~Matt