Just like they did last week with the reset of iCloud backups, Apple has now scheduled a reset of iTunes Match libraries for beta testers on September 26th 9AM PST. At that time, all iCloud libraries will be deleted.
To get ready for the big reset, you will simply have to turn iTunes Match off on your computer and iOS devices. Obviously, this will not affect any of the songs that are physically stored on your computer or your iDevice…
Apple claims this step is necessary in order to, “improve the overall quality and reliability of iTunes Match.”
After the reset of iCloud backups and iTunes Match, it is safe to assume Apple should seed the iOS 5 GM sooner than later.