A few things that may have been mentioned already; either way I'll add my voice:
1. While time trialing in Melbourne, after a few laps I noticed my PB ghost car wasn't around anymore, and no matter how fast I went I was a few seconds behind my "best time". Turns out sometime during the session it recorded my best time as being around 20 seconds - probably a sector time. I hard closed the game from Windows to avoid it recording that time in the system.
2. Online racing with a few guys in Marina Bay, a 20% wet race. With two laps left the safety car came out (first time I've seen it in the game). I was leading and there was a lapped car right behind me. Before the SC appeared I was crossing the start/finish line, and the car slammed on the brakes without my control! It said something like "autoslowing" I came to a stop on the finish staight and had to start up again. The guy behind must have been wondering what kind of idiot I was. Then I caught up to the SC and continued behind it, it was very hard to follow because it was bouncing back and forth all the time (one second it would be a ways ahead, the next second it would be a little closer)! None of the other cars on the grid were doing this. I continued behind it into the last lap, where it stayed out even though the engineer said the accident had been cleared up. I gave it more space this time, but again I came to a stop on the finish straight. Bizarre! Later in the lap, again giving the SC plenty of space while in the middle of the road, suddenly my car was destroyed! The screen displayed the G force of the impact. Impact with what? My guess is that I drove into the SC when it was ghosting backwards, even though it was way ahead at the time.
That's my first experience with the safety car.
Bottom line - never, ever, under any circumstances lead a race when the safety car comes out.
3. In spectator mode, when I tried to spectate a couple of the drivers who were on track, this is the view it gave me:
http://i54.tinypic.com/25i1zlv.jpg
The speedometer and mini-map worked, but the lap times didn't, and that strange white sky with floating grass in it was a static image. I could see proper views of a couple of the drivers.
4. Another online race, this one in Melbourne. A driver joined the session during qualy, and as such he could not set a time. However, when the race started, surprise! That driver was in pole position! No, qualification results were not reversed or random: the winner of qualy was lined up second and the 2nd-best time was in P3.
5. The 11/11 spring setup "cheat" that others have mentioned. I agree it's faster than it should be.
6. Not really a bug, but... when the fuel estimator says "optimal" instead of +1 Laps, there's a good chance I'll run out of fuel on the last lap.
