Thanks for the report. Is this a case of the warning below?

https://docs.python.org/3.8/library/multiprocessing.html#multiprocessing.connection.Connection.recv

> Warning The Connection.recv() method automatically unpickles the data it receives, which can be a security risk unless you can trust the process which sent the message.

> Therefore, unless the connection object was produced using Pipe() you should only use the recv() and send() methods after performing some sort of authentication. See Authentication keys.