The default theme of blender has no `icon_border_intensity` and
therefore only loads the regular icons. When newly loaded theme has the
`icon_border_intensity` set it needs to reload the icon textures so both
icon maps would be loaded.
Without reloading the icons a GPU texture is missing and would crash
blender at first use. Starting Blender the second time it would load the
correct icons and would work as expected.
Jeroen Bakker