Just found what looks like a bug to me. If you are in a race and then go into Shift+U mode, then hit Shift+P to pit and hit ESC, you are no longer able to hit Shift+J to join the race. If you go to the pits, and then hit OK, you can still join the race and everything is fine again. Seems like it doesn't realize you've pitted if you do it when you are in Shift+U, which is why you can't rejoin.

Hopefully that description makes sense, if you try it out you'll see what I mean.

Shift+I also doesnt work in Shift+U. Its true . But not fun .