Sounds like fairly normal operating conditions to me with AC. How warm was the outside temperature before flight because the short flight can't get it cool enough before landing in my experience YYC-YEG even when the a/c is functioning. I've been on far too many flights on this route with AC as described....

Last year I flew AS YEG-SEA on the Dash8-400 and the temperature was an uncomfortable 81F according the front thermostat. I wrote a letter to Horizon about it and two weeks later got a $50 flight voucher.