CRA seems to suggest that where X makes a payment at the direction of Y, X need not issue a T4A to the payment recipient

A Canadian university agreed with a (perhaps, foreign) Ministry to apply funding received by it to pay the tuition of and a monthly stipend to trainees who were accepted into a University program. CRA stated:

The obligation to prepare and file T4A slips and T4A summaries rests with the payer of the amount. The payer is the person who has discretion and control over the funds, and would not include a person who merely disburses the funds on behalf of the payer without having any discretion or control. Therefore, if the University is not the payer of the amount, it is not obligated to prepare and file T4A slips and T4A summaries.

Although it is difficult to generalize, this suggests that where X disburses funds at the direction of Y for services of Z described in Reg. 200(2) (or the amount received by Z is otherwise described in Reg. 200(2)), it is Y rather than X who is obligated to issue the T4A to Z. Where Y is foreign, this may mean that no slip is issued.

Neal Armstrong. Summary of 15 March 2019 External T.I. 2018-0766021E5 under Reg. 200(2)(a).