I am aware of the law
But your examples are not analogous. Kamila's positive test is not due to a medical condition. If she can prove the incredibly strained theory about her grandfather (does her team not realize that people are laughing at them because of this story?) then yes, it could possibly be a defense to a DUI, much like the fermented milk.
But if you are aware of the law, in a strict liability system such as WADA, the test is sufficient. There is no
mens rea requirement, which was the original proposition. I say again, as far as I can tell, motivation is not relevant.