https://wccftech.com/iphone-storage-almost-full-bug-plaguing-users-after-updating-to-ios-15-ipados/

If you recently updated to iOS 15 or iPadOS on your iPhone or iPad, and you happen to see a 'storage almost full' badge, you are not alone.

Although the iOS 15 and iPadOS 15 update went through smoothly for a lot of users, but it left some out there surprised when they opened up the Settings app. At the top, users were greeted with a message saying that their iPhone / iPad storage is almost full. Tapping on the banner took then to the device storage section where the storage wasn't definitely full at all. Obviously a fluke.