About a week ago, we reported on a bug with AdWords/Analytics that can have a negative impact on your ads, cost and ranking of those ads.
In short, the conversion data was not being past from Analytics to AdWords and when you run your ads based off of CPA bidding, without CPA data being passed through, it can have a negative impact.
AdWords customers were told to switch off CPA bidding and on to another bidding logic.
That bug has been fixed late last night and the historical data from the previous days is now catching up.
A Google AdWords representative told me, "this has been fixed and past data will be restored in the coming days."
An updated WebmasterWorld thread has confirmations from advertisers:
Just now I found out: Conversion begin to be imported again.
Till now the data of January 21st can be seen. The data from January 7th to 20th is still missing. Let's hope it will be added in the next couple of days...
Forum discussion at WebmasterWorld.