alternatives with voltanumber-list not working in lyrics

[Hans Aikema via bug-lilypond]

In music the following works fine

\repeat volta 3 {
...
  \alternative {
    \volta 1 { …}
    \volta 2,3 { …}
  }
…
}

However when using the same construct in the lyrics it breaks:

Parsing...
/Users/aikebah/Projects/gitlab-aikebah/el-shaddai-music/src/music/ZZMWE/ZZMWE.ly:36:22:
 error: not a duration
            \volta 2,
                     3 {
Interpreting music...
/Users/aikebah/Projects/gitlab-aikebah/el-shaddai-music/src/music/ZZMWE/ZZMWE.ly:36:24:
 warning: missing volta specification on alternative element
            \volta 2,3 
                       {

ZZMWE.ly
Description: Binary data

The \alternative \volta is documented to take the list of volta numbers for 
which the alternative applies as an argument and the repeats of this type in 
the documentation always use comma-separated syntax I consider that syntax 
breaking for lyrics a bug given that there is no mention of this on the lyrics 
and repeats section (that does contain information on problems due to limited 
support for repeats within lyrics)

kind regards,
Hans Aikema