Wrong alternative numbering when some are empty

[D'Arcy J.M. Cain]

This seems like a bug to me but perhaps someone can explain it.  I have
a piece where the verse repeats nine times with verses 3 and 6 followed
by an alternative.

  \mark \markup \italic "repeat 9 times"
  \repeat volta 9 {
    \BassVerseA
  }
  \alternative {
    { }
    { }
    { \BassBridge }
    { }
    { }
    { \BassVerseB }
    { }
    { }
    { }
  }

  \BassVerseC

So I expect that it will show 3 for the bridge and 6 for verse B but it
shows 1 for the bridge and 4 for verse B.

I understand that I could move the last bar of the verse into the start
of each alternative but that just makes the chart messy.

Oddly enough it plays correctly.

-- 
D'Arcy J.M. Cain
Big Smoke Music
http://BigSmokeMusic.com/ IM:address@hidden