slurs at breaks are wrongly influenced by rehearsal marks

[Toine Schreurs]

The last part of a broken slur (at a line break) is wrong if at
the same time a long rehearsalmark is printed. The slurdirection
is reversed, and the slur is drawn at the right side of the
note, instead of the left side. The slur is extended to the full 
length of the rehearsal mark.

snippet:
%%%%%%%%%%%%%%%%%%%%%

\version "2.9.25"
\layout {
  ragged-right = ##t
  ragged-last = ##t
  indent = 0.0\cm
  \context {
   \Score 
   \override RehearsalMark #'self-alignment-X = #left
  }
}

{
  c'1( \break
  \mark \markup { "long rehearsal mark" }
  c')
}
%%%%%%%%%%%%%%%%%%%%%

A solution could be to disable breaks at rehearsalmarks with simultaneous
slurs, but that's something you want to avoid in a more complex score.

Is there another solution for this problem, or is it a bug?

Greetings,
Toine Schreurs