Closing window does not exit `bash` process on Windows

On Windows 10, if I close an Alacritty window that is running a GitBash shell, the window closes but the `bash` process continues to run. If I issue the `exit` command, then both the `bash` process and the Alacritty window are exited as I expect.

I'm wondering if this is a configuration issue on my side or if there might be a bug in Alacritty.

### System

OS: Windows 10
Version: alacritty 0.4.2 (f68de37)
Windows: ConPTY
Bash: C:\Program Files\Git\bin\bash.exe > version 4.4.23(1)-release (x86_64-pc-msys)

### Config

```
window:
padding:
x: 3
y: 3
font:
size: 10.0
background_opacity: 0.8
selection:
save_to_clipboard: true
shell:
program: C:\Program Files\Git\bin\bash.exe
args:
- --login
- -i
working_directory: F:\
mouse:
url:
modifiers: Control
mouse_bindings:
- { mouse: Right, action: PasteSelection }
```

### Logs

```
[2020-05-05 12:43:34.871819400] [DEBUG] Estimated DPR: 1
[2020-05-05 12:43:34.872814500] [DEBUG] Estimated Cell Size: 7 x 15
[2020-05-05 12:43:34.872814500] [DEBUG] Estimated Dimensions: None
[2020-05-05 12:43:35.273176100] [INFO] Device pixel ratio: 1
[2020-05-05 12:43:35.275175100] [INFO] Initializing glyph cache...
[2020-05-05 12:43:35.291178300] [INFO] ... finished initializing glyph cache in 0.0157781s
[2020-05-05 12:43:35.294177400] [INFO] Cell Size: 7 x 15
[2020-05-05 12:43:35.294177400] [INFO] Padding: 3 x 3
[2020-05-05 12:43:35.298176400] [INFO] Width: 1024, Height: 768
[2020-05-05 12:43:35.333174700] [INFO] PTY Dimensions: Line(50) x Column(145)
[2020-05-05 12:43:35.345179700] [INFO] Using ConPTY backend
[2020-05-05 12:43:35.345179700] [INFO] Initialisation complete
```