bool is explicitly documented to be a subclass of int [1][2], so while it might be an obscure feature, or subjectively not someone's preferred style, I don't see any typing related issue. In general I don't think that treating an object as if it were an instance of one of its base classes is weak typing.
I'd argue that even though it's well defined behaviour in Python, it still appears to me as a programmer as weak typing. For example, Python lets me write:
if 23:
print('hello')
and it'll print 'hello'. But I'd prefer a strongly typed approach where this code would give an error saying, 'a bool is expected here'. Sure it's a subjective thing, and this is just my preference.