ReheasalMark in Staff context is broken - can someone verify this snippet is a bug?

[Adam James Wilson]

There is a  problem when moving the RehearsalMark to the Staff
context.  In the case where the RehearsalMark remains in the Score
context (comment out the layout block below), the first RehearsalMark
aligns to a Clef and the rest align to staff-bars.  This is the
correct behavior.

But if you move the RehearsalMark to the Staff context (retain the
layour block below), the opposite (and incorrect) behavior occurs: the
first RehearsalMark aligns to a staff-bar and the rest seem to align
to Clefs.

\version "2.11.34"

%%{
\layout {
        \context { \Score               
                \remove "Mark_engraver"
        }
        \context { \Staff       
                \consists "Mark_engraver"
        }
}
%%}

\new Staff {

  \bar "|"
  \mark \default
  \clef bass
  c'4 c'4

  \bar "|"
  \mark \default
  \clef treble
  c'4 c'4

}

Should this be filed as a bug?

Best,
Adam