2nd ending time signature strangeness when using Devnull

[address@hidden]

I just ran into a problem that seems to be related to Devnull. The second 
ending time signature reverts to 3/4 time. If I comment out the Devnull line 
then the time signatures are as expected. Am I using Devnull in the wrong way? 
Is this a bug?
Thanks, 
Holland 

\version "2.19.30"

global = {
  \numericTimeSignature
  \time 4/4
}

music = \relative c' {
  \repeat volta 2 {
    c1
  }

  \alternative {
    {
      \time 3/4
      d4 d4 d4 |
      \time 4/4
      c1 |
    }
    {
      %this should be a 4/4 bar, but is treated as 3/4 when Devnull is active
      d4 d4 d4 d4 |
      c1 |
    }
  }
}

%use \music variable to define metric structure, rehearsal marks, etc. for all 
voices
global = {
  <<
    \global %include previously defined global stuff

    %!!!! comment out the next line and the time signature problem goes away
    \new Devnull \music
  >>
}

\score {
  \new Staff {
    <<
      \global
      \music
    >>
  }
}