strange ragged-bottom system layout behavior with explicit \pageBreak

[Martin Straeten]

When forcing a pagebreak the layout behavior of ragged-bottom changes, see 
sample:

%---
\version "2.19"
\paper{
  paper-height = 125
  ragged-bottom = ##t
  annotate-spacing = ##t
}
\repeat unfold 60 \relative { c'4 d4 e4 f4 }
\pageBreak
\repeat unfold 60 \relative {c'4 d4 e4 f4}
%---
The first 60 bars are equally arranged over 2 pages, each having 4 systems —> 
there is enough place for two further systems konnte first page.
The systems for the last 60 bars arranged in a different way: as much systems 
as possible on the page 3

Bug or feature? 

best regards, Martin