Bamboo SSH Task - calling remote script that has switch user (su) fails silently posted to Atlassian Community

I recently submitted this question to the Atlassian Community on a problem I am facing with using the Bamboo SSH Task.

Problem:
I have defined a SSH Task where the commands in the SSH Task input field are:
source /home/myuser/.bash_profile
cd /opt/app/myproject/build/TEST
./deploy_something.sh

Inside the deploy_something.sh bash script, it needs to switch user to be able to start/stop a service (i.e. logstash) that is owned by a different user (i.e. elasticsearch):
su - elasticsearch -s /bin/bash -c "$LOGSTASH_DIR/bin/logstash -f $LOGSTASH_PIPELINES &" > /dev/null 2>&1

This works great when running from within the remote server, but when called from Bamboo SSH task, it dies silently.

I've disabled the "requiretty" and "!visiblepw" configuration via visudo as discussed in https://community.atlassian.com/t5/Answers-Developer-Questions/Execute-sudo-on-remote-agent/qaq-p/523834, thinking it may be similar to a sudo issue. Does not solve the problem.

The Environment details are below:
Bamboo Server: centos-release-6-9.el6.12.3.x86_64
Remote Server: centos-release-6-8.el6.centos.12.3.x86_64

Anyone know a workaround or solution for this?