Not/incorrectly supported kerning condition (crash in LibO)

Analyzing the newest reported bug at https://bugs.freedesktop.org/show_bug.cgi?id=36703, it seems, Graphite has got problem with some kerning conditions, resulting crash under LibreOffice 3.5 beta. See next GDL and the attached test data. (I was be able to fix the crash using user variables for kerning in the GDL file.)

#include "stddef.gdh"
#define p postscript

table(position)

// warning "Vertical overlap between glyphs in items 1 and 1; attachment may be needed":
p("period") { kern.x = 200m; } / p("a") p("period")? _;

// using ellipsis instead of "a"
// strange error message "Unable to get horizontal metrics for glyph 0x00d9" (="Ù"?)
p("period") { kern.x = 200m; } / p("ellipsis") p("period")? _;

endtable;