sqlcl hangs when called using popen from airflow

Question

We're having an issue kicking off a subprocess.Popen within an airflow operator. We're using the following code to kick off sqlcl:

import subprocess
cmd = '/usr/local/bin/sqlcl -V'
p = subprocess.Popen(
    cmd, shell=True,
    stdout=subprocess.PIPE,
    stderr=subprocess.STDOUT,
    text=True,
    executable='/bin/bash')
for line in iter(p.stdout.readline, ''):
    self.log.info('%s', line)
p.wait()
# we have also tried p.communicate() and p.poll() here

The snippet above works when run from ipython but hangs with no output when run from within airflow. Any suggestions?