I´d personally stretch your expected timeline to next friday (21). The earlier you get them, the better, but I recommend to start counting based on official Canada Post timelines (four business days) to avoid excessive anxiety.
My cards were mailed June 6, not delivered yet.
My little regular mail experience in Canada had the worst timeline of 10 calendar days for regular mail (credit cards, mailed May 3, delivered May 13), so I´d count on a timeline of up to 6-7 business days (which can add to 14 calendar days, depending on factors like the day the document was issued and if there are any nearby weekends/holidays in the timeline). If it takes longer, OR if the message in your account changes to "Your document is valid", then you should check for any possible returns to IRCC.
And yes, those timelines are VERY random.