cross-staff beam slope behavior

[Alex Shanin]

> I'm not top posting.
% Hi. Here is the problem I met while typesetting
% a long double-voice cross-staff running-up. I'm
% unsure if there's a shorter way to reproduce it.
% Build 2.10.33 behaves identically.
%
% Upper beam gets sloped ok, lower doesn't at all.

\version "2.11.55"
\paper { ragged-right = ##t }

issue = \relative {
  c,8 [ g'
  \change Staff = RH
  d' a' e' b' ]
  b [ e, a, d,
  \change Staff = LH
  g, c, ]
}

\new PianoStaff <<
  \new Staff = "RH" { \clef treble \time 3/4 }
  \new Staff = "LH" { \clef bass   \time 3/4 }
  \context Staff = RH {
    \voiceOne
    \change Staff = LH
    \issue %%%% slope ok
    \oneVoice
  }
  \context Staff = LH {
    \voiceTwo
    \issue %%%% no slope
    \oneVoice
  }
>>