If you mistype a property on a nullabe or already filled property of a model instance, Django will happily save the model with the mistyped property (which will be ignored because it's not part of the model) without actually modifying anything in database.
Calling that behavior a flaw of Django's ORM is disingenuous.
Sure it does. It doesn't on assignment, as you can modify the object however you like, but it does have AttributeError for accessing a property that doesn't exist.
>>> def with_slots(**kwargs):
... class SlottedClass(object):
... __slots__ = kwargs.keys()
... def __init__(self, **kwargs):
... for k, v in kwargs.items():
... setattr(self, k, v)
... return SlottedClass(**kwargs)
...
>>> with_slots(foo=1, bar='qux').zork = 4
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'SlottedClass' object has no attribute 'zork'