> If I was to submit this as a PR, ...

Please don't jump to writing code yet.  We need to decide what should be done first.  

I'm not really excited about making a change at all.  No users seem to have ever been affected by this.  The CPython code matches what it is documented to do (by the pure python code in the documentation).  In a way, it is just an obscure implementation artifact.

If we do make a small change, I would like it to be 3.7 only.  No need to risk breaking existing code for something that technically isn't even a bug (because it matches the documentation).  As the title suggests, it is more of an oddity than anything else.