Fonts: HW vs. SW

Strange, but true: I use glxUseXFont to create a bunch 'o display lists for the various characters of a font. This works fine in software mode, but not always in hardware mode… Sometimes not all of the text shows up. Not like a letter or two here and there, but entire text objects. Some of them (same font, DLs , etc.) don’t display. I’m not even sure how this could happen? Is this something that might be card-specific, or am I doing something seriously wrong here? It always works in SW mode, but sometimes flakes out in HW.