Previously it was unpredictable, and that's why collections have OrderedDict; which makes sense instead of trusting an implementation detail of CPython from 3.6.
Is not mentioned in the docs: https://docs.python.org/3/library/stdtypes.html#mapping-type...
EDIT: but the behaviour is documented in OrderedDict itself! https://docs.python.org/3/library/collections.html?highlight...
Interesting!