Beam's 'positions' attribute confused by \change

[Yuval Harel]

Hi,

It seems that a \change command after a beam makes the Beam grob's  
'positions' attribute relate to the staff changed to, instead of the staff  
where the beamed notes actually are.

Here's an example:

\version "2.4.2"

RH = \relative c' {
    \time 12/8
    \stemDown
    \once \override Beam #'positions = #'(-6 . -4)
    c8 d e
    \once \override Beam #'positions = #'(-6 . -4)
    c d e \change Staff=LH
    s2.
}

LH = \relative c' {
    \clef bass
    s2. \change Staff=RH
    \stemDown
    \once \override Beam #'positions = #'(-6 . -4)
    c8 d e
    \once \override Beam #'positions = #'(-6 . -4)
    c d e \change Staff=LH
}

\score {
    \new PianoStaff <<
        \context Staff = RH {
            \RH
        }
        \context Staff = LH {
            \LH
        }
    >>
}


Yuval