Theoretically that’s possible, but what makes you think that cannabinoids wouldn’t have that effect on a cat? What evidence do you have of this?
I’ve had multiple cats in my life, and none of them have ever had any sort of adverse reaction to cannabis. Some may not like it, but that’s not really the same thing. And I’ve never heard of anyone reporting any sort of adverse reaction from any of their cats. I realize this is anecdotal, but still.
Even in human beings, a toxic dose of THC would far exceeded what any human could possibly consume (unless an ultra-mega-concentrate stronger than anything ever made were produced, perhaps). One would think the same would apply for a cat.
As for organic structures that don’t get metabolized, often they just get peed out. after all, that’s what happens with excess THC in humans that doesn’t get metabolized. That’s why you can detect it in a urinalysis.