Forza Rewards issues progressAugust 24, posted in the Forza Rewards FAQ:
Originally Posted by: WatchingPolecat 
Hey there, wanted to jump in and give quick update on where we are with Rewards.
FH1 and FM4 credits are now flowing at good rate. There were a couple of issues clogging up the system that slowed our credit sender to a crawl for those titles. These should be fully caught up by this weekend, including all credits for folks who haven't seen them all summer. As long as you've been redeeming, we have those credits and will get them sent.
DLC and Achievement fixes are being worked on and should get deployed soon(tm). These are a bit different from the other game stats, which is why I keep talking about them separately.
Other stats being stuck is a bit of a separate issue that is being looked at as well. We should start to see all titles updating again shortly.
-wp