Since yesterday, my iOS 11.3.1 (on an iPhone SE) is in a strange, beforehand unseen state whereby most of its default apps apparently have become uninstalled somehow (for instance, Maps and Videos are marked with the Cloud-like download item) and iOS proceeds with downloading them from somewhere (hopefully/presumably Apple) anew when I click on their icons (has e.g. happened with Notes and Podcast so far.)
I am wondering: Is this a known phenomenon? For what reason does iOS enter into such a state?
Best Answer
This is called 'Offload Unused Apps' and was a feature introduced in iOS 11.
Source OSX Daily:
To change this setting:
Settings
iTunes & App Store
Offload Unused Apps
and toggle to the desired positionSettings
If this is turned ON, iOS will automatically remove apps you don't use only when your storage is low. To use that app again, as you've discovered, you just tap on the app and it will automatically download back to your device.
You’ll notice that while the feature will remove the app, it will maintain data and documents related to the applications that are offloaded.