I'm recalling a similar situation that I experienced a year or so back, not with SAS but with another airline, even at the time of booking I suspected all along that it would become cancelled, I sputted that the flight, and other flights, had become as if fully booked, there was a delay of a number of days or longer before the airline notified me which I put down to too many cancellations, given these times we find ourselves in, and not enough staff to deal with notifiying passengers, rerouting via other airports, processing refunds etc. all of which I can imagine to be somewhat time consuming.