A friend of mine (she can't use the forums yet) had an issue come up when she logged out of the game. After a lag spike and losing her connection to the server (two separate events, the latter she had to quit out of the game entirely and log back in), she got this error when she quit out of the game.

An unexpected error has occurred. Exiting FINAL FANTASY XIV. 2018-08-02_01:56

KERNELBASE.dll+3A388
dxgi.dll+37705
dxgi.dll+31B8
dxgi.dll+2F84
dxgi.dll+3301
dxgi.dll+2FC7
d3d11.dll+3925D
d3d11.dll+27853
This notice came up twice in a row (clicked OK, it came up once again, clicked OK again, FINAL FANTASY XIV closed). She's on a laptop connecting via WiFi, if that helps.