As early as on December 14th, AdSense publisher began noticing new report options available to them. The new report type, found in the "advanced reports" section directly under the Aggregate data" and "Channel Data" options was named ""AdSense unit data."
This report is suppose to help those who are using the new manage ads feature, which was announced back in October but not launched until mid-November. Many AdSense publishers, like myself, still do not have the manage ads feature, so they won't see this option.
A WebmasterWorld thread and DigitalPoint Forums thread has discussion on people seeing the reports and then it being removed from their reporting area. It appears to me that those reports were a bit off, but I am not sure if all the recent AdSense reporting bugs stem from this manage ads feature feature or not. It seems oddly ironic that all the reporting issues came along with this new manage ads feature, and that Google has been very reluctant to expand the manage ads feature to more publishers.