Problem: ragged-last = ##t gives cramped last line

[Jonas Nyström]

Hi all!

I'm using lilyond throug ScoreRender for displaying music fragments. 

I want to use ragged-last = ##t because short examples shouldnt be wider than needed.
Problem: When the example use more than one system, the last system sometimes is "cramped" — 
to tight formatted when the notes (almost) colliding. 
In the example below, the second system should break after six bars, just like the first system - shouldn't it?
Any ideas how to solve this?

Best regards / Jonas

\version "2.8.1"
\paper  { 
    indent = 0.0\mm
    ragged-last = ##t
    line-width = 6\in
}
\relative {
c d e f g f e d c d e f g f e d c d e f g f e d c d e f g f e d c d e f g f e d c d e f g f e d c d e f g f e d c d e f g f e d  
}