So I was writing code that had multiple write thread and read thread "groups" in a single pool (in a group a few write threads write to a queue that a read thread reads), and I ran into what I think is a race condition with the multiprocessing.Manager() class. It looks managed queues are returned from Manager() before they are actually initialized and safe to use, but it is only noticeable when making many managed queues in quick succession. I've attached a simple demo script to reproduce the bug, the reason I believe this is race condition is because while the sleep(0.5) line is commented out python crashes, but when it's not it doesn't.

Also I'm on windows 10 and using 64 bit Python 3.5.2