When i quit the game , either by logging to character screen then quiting game or just quiting game it seems to be taking a really long time to shutdown. As soon as i click to quit then confirm. Whatever sounds are going on in the character screen or any sound it makes when exoiting the game , the sound will stutter and then the sceen turns black , you can still see the ingame cursor and it takes anywhere from 3 to 5 minutes to exit out of the game completely.
I had the same issue, Then i started spamming Alt + f4 or alt tabbing and closing it via killing the process in task manager.
Needless to say many people are experiencing the issue and its caused by the memory leaks of the game. At least thats what 'we' (the people experienceing it) narrowed it down to.