partcombine - upper voice rests not printed

[Eby Mani]

Note: Seems the mail sent yesterday somehow did not appear in the mailing list 
or a delivery failed message was not generated. 

**********************************
Apologies if this been asked earlier. When using \partcombine, rests on upper 
voice is not printed, but rests on the lower voice is printed.

How do i get to print the quaver rest(critical) in the first measure ?. somehow 
it prints the critical rests in the lower voice.

Thanks,
eby
************************************
\version "2.18.2"

pA = \relative c' {
  %%% partcombine rest is not printed.
  f4 e8 fis r8^\markup "rest" d'8 d d

  d4 r r c~
c8 bes bes c16 g r8 d d'4
}

pB = \relative c' {

  f4 e8 fis g4. fis8
  %%% partcombine rest is printed.
  f8 ees16 d ees4 d r8_\markup "rest" ees8
r4 r8 c16 bes c8 a a' f
}

pCom = <<
  \mergeDifferentlyHeadedOn
    \mergeDifferentlyDottedOn
    \partcombine \pA \pB >>

\score {
  <<
  \new Staff = "no-part-combine" \with { instrumentName = "default" }
  <<\pA \\ \pB>>
  >>
}

\score {
  <<
    \new Staff = "part-combine" \with { printPartCombineTexts = ##f 
instrumentName =  "partcombine"}
    \pCom
  >>
}