Using a custom font (any TTF - I've tried several) causes a display problem. The game displays the font at a different size in different places. The loading screens, text screen, and console buttons and values show at the expected size. However a much larger size is displayed on the HUD.
eg a setting of 12 displays the font quite small on the console screens etc, but at a reasonable size on the HUD - a setting of 30 displays the font at a good size on the console, but much too large on the HUD.
Oddly, this phenomenon does not happen with the default font.