A poster on the MacRumors forums discovered the bug after trying 'Reset All Settings' to improve iOS 8 performance on an iPad 3.
Because iOS 8 was so sluggish on my iPad 3 I reset all settings (No data or media will be deleted) and sped it up BUT deleted my iWork data! Then promptly synced and deleted it in iCloud.I have public beta of Yosemite so can't roll back via time machine. I have no pre iOS 8 backups in iTunes or iCloud to revert to (well iCloud device backups don't contain cloud documents and I should have iOS 7 backups in iTunes but can't find any. iCloud has no trash like dropbox. They seem gone forever.
The files are being deleted despite the function clearing stating, "No data or media will be deleted." As you may know, the option is simply meant to reset user preferences.
At this point it appears that only iWork documents are being wiped. MacRumors tested the bug themselves and found that all iWork documents stored in iCloud Drive on the iPhone and on iCloud.com were deleted. After some time for syncing, all of the documents were deleted off a Mac running OS X Yosemite as well. Preview and TextEdit documents which don't have a corresponding iPhone app were fine.
Unfortunately, there's no easy way to recover these documents. Several people who have suffered lost files are in contact with Apple Support. One said Apple was waiting on engineers to investigate. Another said his account was in troubleshooting mode as Apple attempted to recover the data.
We strongly recommend you do not use the "Reset All Settings" option if you have iCloud Drive enabled.
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