Azure functions core tools: func start on linux agent won't stop after receiving a SIGTERM command?

Question

func start on linux agent won’t stop after receiving a SIGTERM command:

-We have a build pipeline that runs a node application
-Integration tests are then ran against this application
-On completion of the unit tests, a SIGTERM command is sent to terminate the function process
-Since upgrading from Azure functions core tools version 3 to version 4, this functionality has stopped working.
-Node 14 and 16 have both been used, however both give the same issue.
-The build agent doesn’t log out anything from the task in the pipeline when this command is running, the task just hangs until its eventual timeout after an hour.

Further info:

This error occurs when we upgrade the Azure Functions Core Tools version from 3 to 4, and happens when executing the simultaneous commands, one to run the function and another that sends the SIGTERM command upon completion. This happens in the terminal on our local Mac machines (both with an M1 chip and Intel chip) as well as in the pipeline.

We have tried three different approaches to executing the two simultaneous commands as is required by the pipeline stage and debugged to confirm that the problem is not the second process.

It doesn’t timeout when running with Azure Functions Core Tools version 4 on a Windows build agent (though we require ubuntu).

It also doesn’t timeout when running with Azure Functions Core Tools version 3 on any build agent.