Originally Posted by
Flauschie_Mr
Yes, it is a bug. It happens often, at least on the routes I fly.
When I noticed this I was initially worried too, but contacted TK and they confirmed the quoted mileage accrual was incorrect. My flight did earn according to the booking class.
This would be good news if the miles are indeed credited based on the actual distance. After checking some affected routes, I found that the issue is not related to the booking class. It appears that TK omitted one segment when calculating the total mileage.
For example, in this route, the BOS–IST leg was not included in the mileage calculation. In another route I checked, it was the segment departing from IST that was missing.