Version >2 13.4 not staying within bottom margin

[Nick Payne]

Staring with v2.13.4, and continuing with 2.13.5 and 2.13.6, one of the 
scores I have been setting has the bottom stave on two of the pages 
positioned too low. The bottom margin is set to 1.5cm. On one of the 
pages the bass notes are positioned lower than this, so low that they 
are outside the printable area for my laser printer. On the other page, 
the bottom stave is positioned so low that some of the notes actually 
vanish off the bottom of the page. If I build the score with 2.13.3 then 
this problem doesn't happen, so there seems to have been something 
introduced with 2.13.4 that doesn't correctly vertically position this 
score. I'm not specifying any vertical settings or number of systems per 
page etc

I haven't been able to reproduce the problem with a small example, and 
the score is too large (~90Kb ly file) to atach here, but I can e-mail 
it if anyone wants to have a look at it.

Nick Payne