No, I am not saying that.
I'm saying that when the Python language specification prescribes a behavior, and the Python implementation in C has a different behavior because it does something which the C language specification considers undefined, then the Python implementation in C does not comply with the Python language specification.
I'm saying that it's incorrect to say that non-compliant behavior with respect to the Python specification is the same thing as undefined behavior. It makes no sense to say something is undefined when the specification defines what is supposed to happen.
I suspect that is where we differ. It seems to me that if a C program does something that results in undefined behavior according to the C spec, it is undefined behavior period, regardless of any other factors, because the spec says it's undefined and that's all that matters.