RuntimeError: Second simultaneous read on fileno X detected

[Moshe Elisha]

Occasionally when executing the attached workflow you will get the following error:

Failure caused by error in task 'collect_executors_hostnames': os-mistral-02;

error in task 'collect_executors_hostnames': RuntimeError: Second simultaneous read on fileno 16 detected. Unless you really know what you're doing, make sure that only one greenthread can read any particular socket. Consider using a pools.Pool. If you do know what you're doing and want to disable this error, call eventlet.debug.hub_prevent_multiple_readers(False) - MY THREAD=<function on_read at 0x6690c80>; THAT THREAD=FdListener('read', 16, <built-in method switch of greenlet.greenlet object at 0x66e4230>, <built-in method throw of greenlet.greenlet object at 0x66e4230>);

Mistral logs are enabled on debug level but I could not find anything relevant there.
This is a Mistral HA installation with 3 APIs, 3 Engines and 3 Executors.