Originally Posted by Wurm
It still shows it as missing, doesn't affect my UI at all as far as I can tell so I'm not worried about it
As long as you can see the "scoreboard" font on the XP bar and the italic script font (group member numbers e.g.) then you can ignore it.
You can try in the \UI\fonts folder to delete all files with Speedline and Highspeed in the name, and re-download. If the game is running during an update, sometimes the zipped version will get downloaded but can't unzip due to the file being locked. I'll see if I can smooth this out in the next version of the updater.