Not an issue with route, but with method of booking - only web bookings qualify for the 20% bonus, phone bookings make the itinerary ineligible.

The system does have an issue if you book online, but subsequently call in to make a modification (even if the only way to do that change is by calling) - it will not attract the tier miles bonus automatically. For that, you need to call in and complain to them, then email them, for it to be rectified.