Yes, this is a design flaw in the Python 2 import system - it derives `__package__` from `__name__` the first time it needs the information and `__package__` isn't already set.

The problem was fixed for the Python 3 series by way of PEP 451, which made substantial changes to the way module initialisation works, allowing the import system to instead derive `__package__` from `__spec__` as part of module creation.

Depending on your reasons for being interested in this, the `importlib2` package may be of interest: https://pypi.org/project/importlib2/

(Judging from the version number, Eric last updated that for Python 3.5, which means it will include the PEP 451 behaviour)