Had a new issue (that was also new for the agent I spoke to) today
1) priced out a fare YYC-LHR return on Matrix, with comfort fare, W booking class for lower eUp requirements, use deeplink to Air Canada website
2) website shows the price, double check that fare details show it as a W comfort fare, fully refundable
3) go through the process, traveler details, choose seats etc
4) putting in payment details - reprices at a lower price, double check - its still comfort fare still in "W" , so buy the ticket
5) booking confirmation page shows I booked a comfort fare
6) email confirmation and "manage my bookings" show a standard fare

Luckily I screenshotted the booking confirmation page. A very helpful phone agent just voided the original booking and booked me what I wanted, at the original price that I could quote to them...