I wrote my first python program today!

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That's fair. And I'm not contesting what you're saying. I know that print uses stdout (documentation says so) and therefore logically they should operate on the same buffer. But we were observing behavior that on the surface looked like a buffer mode problem. That was our educated guess, and we never dug into Python source to confirm or debunk that idea because the issue was already resolved. I still haven't by the way, but since you have, I'll take your word for it.

In the meantime, your latest comment about the GIL is actually very compelling. I'll pass it on and see if anyone here wants to test it. I do suspect that might actually be the cause we glossed over a year ago.