\relative c'' {
<< {
d8. e16 c8. d16 b8. c16 a8. b16
} \\ {
c8[ b] b a a[ g] g f
}
>>
}
%=============================
Lilypond is alternately placing the dotted eighth notes in the upper voice to the left and then the right of the colliding eighth notes in the lower voice, rather than consistently placing them on one side. Its much easier to read if the offset is consistently to one side.
I tried using \override NoteCollision #'prefer-dotted-right = ##t but this made no difference. Is there any fix short of using a whole lot of manual \override NoteColumn #'force-hshift = #value (there a quite a number of bars like this in the piece).