Originally Posted by
canadiancow
For unlimited passes, you get it for the "purchase".
For credit-based passes, you get it as you use the credits. This has always been the case.
And for clarity the SQD earned on a credit-based passed is the value of the credit less any applicable taxes/fees that AC still remits on the ticket. This will vary by itinerary and can be subject to FX fluctuations over time on international flights.