NoneType object has no attribute fileno

I am running Redash with Kubernetes using Bitnami helm chart and the adhocworker container often crashes with the following error in the log. Can you please help me fix it?

[PID:8][CRITICAL][MainProcess] Unrecoverable error: AttributeError("'NoneType' object has no attribute 'fileno'",)
AttributeError: 'NoneType' object has no attribute 'fileno'
[PID:8][WARNING][MainProcess] Traceback (most recent call last):
[PID:8][WARNING][MainProcess] File "/usr/local/lib/python2.7/multiprocessing/util.py", line 277, in _run_finalizers 
[PID:8][WARNING][MainProcess] finalizer()
[PID:8][WARNING][MainProcess] File "/usr/local/lib/python2.7/multiprocessing/util.py", line 207, in __call__
[PID:8][WARNING][MainProcess] res = self._callback(*self._args, **self._kwargs)
[PID:8][WARNING][MainProcess] File "/usr/local/lib/python2.7/site-packages/billiard/pool.py", line 1697, in _terminate_pool
[PID:8][WARNING][MainProcess] inqueue.close()
[PID:8][WARNING][MainProcess] AttributeError: 'NoneType' object has no attribute 'close' 
stream closed

Maybe related? https://github.com/celery/celery/issues/3179

Redash doesn’t use Celery still. I think these type of issues drove that decision.

I am using Version: 8.0.2+b37747 (a9d7ca43)

I am also getting AttributeError: 'NoneType' object has no attribute 'close'

Does anybody has any clue why I am getting these errors?