Leading grace note in alternative ending

[Patrick Karl]

The following input results in two problems:

  *  The following message appears in the log file:

        warning: already have a volta spanner, ending that one prematurely

        I have no idea what that means, nor where to go to find out.

  *  The output pdf file is flawed.  Each alternative ending is  
duplicated, with the grace note being placed into the first of the  
duplications.

Note:  The problem disappears if I eliminate the "T" music and staff,  
or if I add a corresponding grace note to the rests in the  
alternative endings for the "T" music, or if the grace note is not  
the initial note in the alternative endings.

\version "2.12.2"

A = \relative c'' {
        \repeat volta 2 {
                f1
        }
        \alternative {
                { \grace f8  g1 }
                { \grace f,8 g1 }
        }
}

T = \relative c'' {
        \repeat volta 2 {
                R1
        }
        \alternative {
                { R1 }
                { R1 }
        }
}

\score {
        \new ChoirStaff <<
        \new Staff { \A }
                \new Staff { \T }
        >>
        \layout{ }
}

I am attaching the pdf output.

Variatio_25R_dbg6.pdf
Description: Adobe PDF document