Exiting terminal while running `npm` in a pane does not terminate processes from terminal

[fisher60]

Windows Terminal version

1.16.10261.0

Windows build number

10.0.19045.0

Other Software

Node.js v16.14.2

Steps to reproduce

1. Open Windows Terminal
2. Split panes
3. Start a process in one pane (I was using npm run start to run a local website with React)
4. Observe website running in web browser
5. Use the x button on the windows terminal window to exit windows terminal
6. Background process is still running and website is still working in web browser

Expected Behavior

When quitting windows terminal, background processes should be stopped. The local server running the React website should also be terminated when windows terminal exits.

Actual Behavior

Background process continues running indefinitely. Task manager does not indicate any windows terminal tasks running in the background. The background task appears to be buried and is difficult to discover so the easiest way to terminate the process is to restart the machine. Restarting the machine terminates the background process and website is no longer hosted.

[fisher60]

This issue seems very similar to #541

[zadjii-msft]

Pretty confident that this isn't #541 - that was a specific bug from like, almost 4 years ago now.

If anything, I'd think that #14544 would have helped here. Can you try this with Terminal Preview (v1.17), and see if that fixes this/?

[fisher60]

This issue is still reproducible for me on preview version 1.17.1023