Looks like the SWISS booking engine is just booking a 'retaining' faux booking segment to keep the PNR active till 1 Dec 2002.

You see, once flights have passed, PNR's get purged or 'deletd' from airline CRS's. The booking engine that is doing the reservation is not with SWISS themselves but through a third party. they would need this 'active' segment just in csae of 'internal' auditing. Nothing to do with you really.

You will get your bonus miles after your flights. Not after the date on the PNR.