Dynamics clashing with stem of cross-staff knee beam

[Caio Barros]

I don't know if this is old news but it seems that the dynamics texts clash with the stems of cross-staff knee beams:

\version "2.12.3"

\new GrandStaff <<
  \new Staff = "PnRH" {
    \clef "F_8"
    \relative g,, {
      \override Beam #'auto-knee-gap = #1
      gis8 \fff \change Staff = "PnLH" a, \fff \change Staff = "PnRH" r4
    }
  }
  \new Staff = "PnLH" { \clef "F_8" { s4 r4 } }
>>

got an arrow on the knee...