Über display in Team Fortress 2
This seems to be a problem with a corrupt file for the uber letter U. Its possible that they will fix this bug eventually but one thing id recomend you try is just reinstall tf2. This will give you clean, uncorrupt, current files of the game and should fix the problem. This can be acheived by right clicking the game in your library and clicking: delete local content. After this you can re install the game from the steam store. I know its time consuming and annoying but the first solution to any minor bug or corrupt file is a clean reinstallation.