I've tried your quick tests a few times but couldn't reproduce it immediately. The problem is a bit hard to reproduce anyway because launching Python processes can go well for a long time (many days; launching many processes every minute) until suddenly all NEW processes get aborted. It seems as if somehow something in the relation to the parent process goes wrong somehow. I've seen it happening with Python as the parent process but also with a plain shell process as the parent.
Just starting Python (python -c "x = 1") can be enough to trigger this so it's not something which can be blamed on some library.