Not Working: Redaction of Spark Environment Variable

Question

I am using the following to add a spark job step to a running emr v5.11.1 cluster on AWS, using python 3.6.5 boto3 and spark 2.2.1:

myemr = boto3.client('emr',region_name=os.environ['AWS_DEFAULT_REGION'])            
response = myemr.add_job_flow_steps(
            JobFlowId=my_emr_id,
            Steps=[
                {
                    'Name': key,
                    'ActionOnFailure': 'CONTINUE',
                    'HadoopJarStep': {
                        'Jar': 'command-runner.jar',
                        'Args': [
                            'spark-submit',
                            '--deploy-mode', 'cluster',
                            '--master', 'yarn',
                            '--conf',  'spark.yarn.appMasterEnv.my_password=sensitive_value',
                            '--conf',  'spark.redaction.regex=password',
                            '--class', 'com.myApp', 's3a://myjarurl.jar',
                            '-c', 's3a://s3bucket_myconfig_location',
                            '-w', 'myconfig.json',
                            '-e', 'prod',
                            '-n', 'demo'
                        ]
                    }
                }
            ]
        )

The step is running ok and able to access the yarn environment variable. But the sensitive_value is not redacted from logs or AWS EMR Console, steps tab. I see --conf, spark.yarn.appMasterEnv.my_password=sensitive_value displayed in both.

I would like for either the variable spark.yarn.appMasterEnv.my_password to be completely removed from logs and console, or the sensitive_value to be replaced with something like ***.

Reading the apache spark doc https://spark.apache.org/docs/2.2.1/configuration.html I thought this would work. Appreciate any suggestions.