I don't have a definitive answer for you, though it makes sense that IRCC/CBSA would want to know from the US why it denied your visa(s) and see if that pairs up with your explanation. An IRCC call center agent once told me that Canada and the US very closely share intelligence on people traveling in and out of either country. And
@USProgrammer once pointed out to me how there is already a high degree of information sharing between the Anglo-Saxon countries of Australia, Canada, New Zealand, the UK and the US. (I'm not sure the level of scrutiny or cooperation is the same with the Schengen Area or other parts of the world.)
Maybe a month from when you raised the CSE you could phone the call center to see if any notes have been made in relation to the CSE? That's all I can think of at the moment. Good luck!