https://arstechnica.com/gadgets/2019/11/apple-fixes-background-app-bug-with-ios-and-ipados-13-2-2/

Today, Apple released a minor update for the operating systems running on iPhone, iPad, and iPod touch devices. Labeled iOS 13.2.2 (or iPadOS 13.2.2 for the iPad), the key bullet point in this update is a fix for a widely reported (and apparently RAM-management-related) bug in iOS 13 that saw apps quitting and losing their state while running in the background.