Comment 18 for bug 145604

Tracked down the apparent cause to libcairo's debian/patches/02-cairo-1.4.8-lcd-filter-2.dpatch.

The bug reveals itself if sub-pixel rendering is enabled and rgba_order 'VRGB' is selected.

 $ gconftool-2 -a /desktop/gnome/font_rendering
 rgba_order = vrgb
 antialiasing = rgba
 dpi = 96
 hinting = full

Changing it to any of the other options (vbgr, rgb, bgr) using

$ gconftool-2 -s /desktop/gnome/font_rendering/rgba_order -t string "vbgr"

and restarting Compiz (or disabling/re-enabling it) will clear the issue.

Working on a fix.