I'm not really answering your question, but I'd like to express some things I learnt about that pay gap. One of the reasons why international students may have a pay gap from domestic is because they will often take any job on the market so long as:

1) It's a secure

2) The company is willing to sponsor their PR applications

Source: https://www.stcatharinesstandard.ca/news/niagara-region/2019/09/25/i-ve-given-up-everything-explosive-growth-in-international-students-comes-at-a-steep-cost.html

For the international students that do make it in Canada's private industry, this mindset often creates the notion that international students are "bootlicking" and "submissive" among Canadian companies. This in turn allows them to essentially exploit international students for additional labor, while dangling the prospect of Canadian Permanent Residence above their heads.