Which month was your latest travel to Canada? I am talking about traveling without POE for the first time. In November, the airline staff asking me to show the letters or the permits directly at the gate along with ArriveCan app.
Of course, in 2016 it was super different than now. I do see that the entry now is not as strict as it was back a month and a half ago. It does make me happy, but, still, just because we are still in Canada being almost closed each person who desires entry should be extra prepared. I wouldn’t fly without the POE letter. OP should not worry, their letter will eventually come in around this week