barcheck bug?

[David Bobroff]

When I run Lily 2.5.16 on the following example I get barcheck failures.

%% file ob.ly

\version "2.5.16"

oboeOne = \relative c'' {
  \key d \major
  r8
  R2.*3
  r4. e8-\p-( d cis-)
}

oboeTwo = \relative c'' {
  \key d \major
  r8
  R2.*4
}

\score{
  \relative c''{
    \partial 8
    \time 6/8
    \context Staff<<
      \set Score.skipBars = ##t
      \partcombine
      \oboeOne
      \oboeTwo
      
    >>
  }
}

%% end file ob.ly

Interpreting music...
ob.ly:13:2: warning: barcheck failed at: 1/8:

  R2.*4
Interpreting music...
ob.ly:6:2: warning: barcheck failed at: 1/8:

  R2.*3

ob.ly:6:2: warning: barcheck failed at: 3/8:

  R2.*3

The output, however, look ok.  Also, if I run the parts separately I get
no barcheck errors.  If I run the parts together in a score it's ok.  It
is only when I use \partcombine.  Is this a false barcheck failure or am
I overlooking something in my input?

-David