Senior actually renounced his Canadian citizenship when he received US citizenship (maybe before when he applied), but in his bio he says he renounced Canadian citizenship.
Which is additional circumstantial evidence that he renounced his Cuban citizenship when receiving US citizenship. Otherwise, he would have renounced both at that time.
What are you actually trying to say?
He was only in Canada for eight years and he didn’t become a US citizen until 2005. What’s your point? Do you disagree with the timeline?