Time signature change in first alternative causes different behavior depending on number of staves

[Jörn Eichler]

Hi to everybody,

this is my first post to this list. I experienced a problem in v2.19.83
when I tried to produce orchestral parts from a score. Since I couldn't
find it on the issue tracker, I hope it's OK to post here:

\score {
  <<
  \new Staff {\relative c {\repeat volta 2 {\time 2/4 R2 |}
\alternative {{\time 3/4  R2. |} {r4 r r |}}}}
  \new Staff {\relative c {\repeat volta 2 {\time 2/4 R2 |}
\alternative {{\time 3/4  R2. |} {r4 r r |}}}}
  >> }

Both staves are the same and the time signature change in the first
alternative (to 3/4) is kept for the second alternative (the bar with 3
quarter rests).

However, if you comment out one of the staves, v2.19.83 gives an error
and silently continues with 2/4 in the second alternative (which gives
one bar with 2 quarter rests and another bar with one rest), while
v2.18.2 still keeps the change to 3/4. So v2.19.83 behaves differently
when there's only one staff.

Jörn