This is a demo project for NSJSONSerialization crashes on iOS 13 when a string cannot be transformed to UTF-8 string, feedback submitted to Apple FB7458717
Download the demo project, run on iOS 13 devices (with Zombie object enabled), and it crashes.
To generate an error, and not crash the application "Error Domain=NSCocoaErrorDomain Code=3852 "The string 0xXXXXXXX failed to convert to UTF8" UserInfo={NSDebugDescription=The string 0xXXXXXXX failed to convert to UTF8}"
Crashes on iOS 13 devices with a "-[NSError retain]: message sent to deallocated instance" message
It works on iOS 10, iOS 11, iOS 12 devices. I think it's a regression.