partcombine problems

[Orm Finnendahl]

Hi,

 I'm having terrible problems with partcombine. In the following code
bars 2 and 3 only show the first quarter rest.

\version "2.19.5"

MusikObEins = {
R1 | % 214 
\partcombineSoloI r4 r8 < b >16-> \sf r16 r4 r4 | % 215
R1 | % 216 
\partcombineSoloI r4 r4 \times 2/3 { r8 < gis' >8-> \sf r8 } r4  | % 217
R1 | % 218 
}

MusikObZwei = {
R1 | % 214 
R1 | % 215 
\partcombineSoloII r4 \times 2/3 { r8 < gis' >8-> \sf r8 } r4 r4  | % 216
R1 | % 217 
R1 | % 218 
}

\new Staff {
      \clef G \partcombine 
      { \MusikObEins }
      { \MusikObZwei }
}

I tried all kinds of combinations of \partcombineSoloIOnce,
\partcombineSoloIIOnce \partcombineAutomatic in all kinds of places,
but couldn't work out the mechanism.

Can someone shed a light on this or is it a bug?

--
Orm