Didn’t read the law, did you?
5.2: A person who is a Canadian citizen under paragraph 1(b) ceases to be a Canadian citizen upon the expiration of three years after the day on which he attains the age of twenty-one years unless he:
Either is living in Canada or files a declaration of intention to retain Canadian citizenship.
Since it is likely neither applies to Cruz, he has no citizenship status with Canada.
This law is from 1946, and it is at least possible the law has been changed since.
BTW, this issue of dual citizenship applied to Winston Churchill, who was a dual citizen of the US and UK till his 21st birthday.
If it's a law, I most certainly didn't bother to read it. No law can affect the meaning of the term "natural born citizen" so it is a waste of time to look at any which purport to do so.
5.2: A person who is a Canadian citizen under paragraph 1(b) ceases to be a Canadian citizen upon the expiration of three years after the day on which he attains the age of twenty-one years unless he:1(b) is "born outside of Canada elsewhere than on a Canadian ship"Either is living in Canada or files a declaration of intention to retain Canadian citizenship.
Doesn't apply to Cruz.