FM4 "no rewards" issue UPDATE: Solution
Thomas Jackermeier
Member
UPDATE
Fanatec wheels are too good to be true?
Thanks to the great feedback. Because of your feedback we have been able to reproduce it. It always happens if you do an extreme clean lap without any countersteering. The most easy way to reproduce it is on an oval.
Special thanks to our members FakeThinkpad and kartman21 who detected the solution.
What happens? The Fanatec wheels allow minimal movements of the steering wheel and extreme precise manouvers so that the game apparantly thinks that the user must be cheating as this cannot be achieved by a human.
The better you drive the more often it happens. It is independent from the steering angle but a clean lap is more likely if you use higher sensitivity like 900°. In theory it can happen with a controller or other wheel as well but so far I was not able to proof that because it is hard for me to drive clean without our wheels. 
Solution:
1. Make sure that you make at least one drift with countersteering per race
2. Reduce your steering angle to 270° to emulate the MS wheel which makes it harder to drive clean but avoids the issue more likely.
Of course, T10 is working on a patch to solve this issue but it takes time until those things go through all internal testing so please be a little bit patient.
IT IS NO LONGER NEEDED TO ASNWER THE FOLLOWING QUESTIONS:
It seems that we had aerver issue so my last post on this subject was lost.
I would like to ask you again to help us to reproduce the problem so please let me knowthe following.
1. Did this issue already occured to you? (how often)
2. What Xbox console version are you using?
3. What sensitivity did you use when the issue occured?
4. Did you find any setting or solution where this issue did not occur?
5. Did it happen with SEN at 270 (this emulates the MS wheel)? (If yes, how often?)
6. What wheel do you have?
7. Did this happen to you or have you heard of that this is happening with other wheels or controllers as well?
8. What version of the game do you have? (demo, full, NTSC, PAL, updates)
9. Did you make a full installation (disc 1) on hard disk?
10. Did you turn on the Xbox console with the Xbox button on the wheel or with the power button on the console?
It seems that not everybody driving a Fanatec has this issue so there must be a difference. It could bethat setting the sensitivity to 270 would solve the issue but we need to confirm that. We only received one FM4 copy so far and it works on 900 as well on our system but this version is not a retail version.
I also saw a report that saving the difficulty settings after loading the race can avoid the issue.
There are already threads in other forums and I would like to list those for reference:
Video: 
http://forums.forzamotorsport.net/forums/thread/4861891.aspx
http://www.forzaplanet.net/forum/showthread.php?t=32
http://forums.forzamotorsport.net/forums/thread/4879072.aspx