No, provided the Canadian investor holds at least fifty per cent and actually controls the business. Ownership above half satisfies the nationality test, and the operating agreement must not hand control to the minority partner.
Half the ownership and real control, both on paper
The enterprise must be at least fifty per cent owned by treaty nationals, and the investor must develop and direct it, ordinarily shown by owning at least half or holding operational control. A sixty-forty split with a Canadian majority meets the ownership test. The control test is where a founder who stays on can create a problem.
Agreements that require unanimity for hiring, spending above a low threshold, taking on contracts or changing the business plan give the forty-per-cent partner a veto that can amount to joint control, and joint control by a non-treaty national undermines the develop-and-direct requirement. The remedy is drafting: reserve those decisions to the majority owner or to a board he appoints, define the founder's role as an employee or minority manager reporting to him, and make sure the buy-sell provisions do not let the founder reacquire control on a trigger the investor cannot manage. Accepting the seller's standard form unchanged is an avoidable risk.
A first review should compare the incorporation documents, operating agreement and purchase terms line by line for who appoints managers and approves ordinary spending. Hypothetical example: a Canadian mushroom grower acquires sixty per cent of a packaging company, but the minority seller can block every supply contract; revising that veto is more useful than adding another ownership certificate.