I am trying to use testResultsProcessor and exported a function as

module.exports = async function(data) {

//get data I need from here

//call TestRail API and update the test run
await callTestRailAPI();

return data;
}

On my local machine, it works fine, the results are uploaded to Testrail.
The weird stuff happens when I run a job in CircleCI: the tests are green, the results are uploaded to TestRail, BUT the job is fails with the following error:

Exited with code exit status 1
CircleCI received exit code 1

I have figured out that this due to the async function exported.
Also tried this way:

module.exports = function(data) {
(async function() {
await callTestRailAPI();
})()

return data;
}

....but the async block is not called.

Does anyone have any clue on this?