You are right ! Some people received it so fast. Sometimes, i have difficulty to understand how IRCC proceed.Thanks I don't understand why some people receive it in a 7-10 days delay and others more than 3 weeks. I think when IRCC says in the letter they have mailed it, I think they mean they press the ok button for printing like a government cheque..
Update : We got home at 4:30 pm today and the work permit letter was at the door ... so weird ... but we got it ! Maybe poste canada dropped it off at the neighbor's by mistake, I don't know! I am pretty sure you will received your’s soon