I think an update was made to the
eq2ui_mainhud_guild.xml file for the 91-95 adventure level gained events that's causing yours to show a blank (black) icon. I renamed your file in the UI to load the default one and I can now see the icon for those. So, it seems to be something in the xml file and not one of the .dds files.
It's a minor cosmetic thing but I thought I'd let you know. Keep up the great work.