And normal it isn't. Yes, the 1308 update added a new feature called Storage Check which was designed to help empty the temporary cache files in the "other" category where native storage from the Nokia Lumia 920 and other models has been disappearing to. As we've seen recently with the Apple iPhone and the recent updates from iOS 6.1.1 to 6.1.3, sometimes correcting one problem opens the door to another. Just the other day, we explained how iOS 6.1.3, which was sent out to correct a problem with the lock screen, has apparently been the cause of a battery drain on some iPhone variants.
So now it is up to Nokia to quickly send out another update to fix this problem. After all, a smartphone without network connectivity isn't too much of a phone and is far from being smart.
source: Reddit via WMPoweruser