Bug in \chords in latest developer version?

Hello,

I found very strange behaviour of \chords when used together with
\numericTimeSignature. Check the following code:

\new Score {
<<
\chords { c1 g c g }
\relative c' { \numericTimeSignature c4-1 c c2 d4 d d2 e4 e e c e2 d \bar
"|." }
>>
}

When running it on LilyBin, it compiles correctly with the latest stable
version, but with latest unstable, it shows no notes or staff, but only a
line of chords. I tried to move the \numericTimeSignature to different
places, but neither worked: Sometimes I got the chords below my staff,
sometimes I got an extra staff with just the timeSignature - I think the
place where I have it should work.
Are there any changes in the unstable version to this part, or is it simply
a bug?

Kind regards,
SK