Django inconsistency around setting TZ into the environ depending on how settings are configured

bad.py

>>> import os
>>> os.environ['DJANGO_SETTINGS_MODULE'] = ''
>>> from django.conf import settings
>>> settings.configure(TIME_ZONE='UTC')
>>> os.environ['TZ']
KeyError...

good.py

>>> import os
>>> os.environ['DJANGO_SETTINGS_MODULE'] = 'valid_path_to_settings'
>>> from django.conf import settings
>>> settings.TIME_ZONE
...
>>> os.environ['TZ']
...