Comment #1 on issue 2586 by [email protected]: StaffSymbol thickness override and imperfect ossia
http://code.google.com/p/lilypond/issues/detail?id=2586
A quick search turned up a couple of issues that might be related: http://code.google.com/p/lilypond/issues/detail?id=2205 http://code.google.com/p/lilypond/issues/detail?id=2155
