The Launch toast continues to run even after the window closes.
I also noticed that folders for CrashReportClient.ini are being generated in the Saved > Logs folder for the project as well.
Window closes, UE4Game continues to run in System Monitor, and in the UE4Editor output log there is "Signal 11 caught. Malloc Size=131076 LargeMemoryOffset=131092" as the last two line.
After using the "exit" command in the console, the window and UE4Game both exit cleanly.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-37536 in the post.