--kill-others --kill-signal=SIGINT exits process with code 1

I don't know if this is a bug or a feature request or if I'm simply not understanding how to properly use this package.

• Description:
  I'm trying to run a web server, then run some e2e tests. When the tests complete successfully, the web server process is ended with SIGTERM, causing NPM to think the tests failed.
  If I don't kill the web server, the task keeps running forever/times out.

I've tried concurrently --kill-others --kill-signal=SIGINT "start server" && "run e2e tests"
as well as concurrently --kill-others --success last "start server" && "run e2e tests"

• Expected Behaviour:
  Processes exit with code 0, NPM thinks (rightfully) that tests pass.

• Environment:
  In an Azure devOps pipeline running Linux 5.15.0-1074-azure,
  v18.20.5,
  Concurrently 9.1.0

• Reproduction: A way to reproduce the issue
  concurrently --kill-others --kill-signal=SIGINT "start server" && "run e2e tests"
  or concurrently --kill-others --success last "start server" && "run e2e tests"

Would you be able to see whether I'm doing something wrong if this is a feature request or bug?
Many thanks.

Start by running the reported concurrently commands with --kill-others, --kill-signal=SIGINT, and --success last on Linux. Trace the signal and exit-status handling for the server and e2e commands; done means successful tests terminate the server without causing the overall process or npm to exit with code 1.