A newly found bug in iOS 12.1.3 seems to have broken the Alt + Tab keyboard shortcut for switching between apps on iPad devices. The bug prevents users from selecting the apps they want to switch to when releasing the Tab key.
When using a keyboard with iPad on iOS 12.1.3, you can press the Alt + Tab keyboard shortcut to bring up the App Switcher, and then continually press the Tab key to get the app you wish to switch in view, however, releasing the Tab doesn’t open the app like it used to before iOS 12.1.3 update. You’ve to touch the app icon you want to switch to from the screen.
There’s no workaround for the issue as of now. If you’re seeing this on your iPad too, be sure to send feedback to Apple so we get a fix in the next iOS update.