I have this issue on a weekly basis- sometimes on A fares that are first class fares booked in A to begin with, other times and more often this happens when I initially book amd economy class ticket and chamge my mind within 24 hours of booking and pay the fare difference to buy up to first.

Most often agents will try to tell me that my tickets were upgraded even though they are paid first fares.

I spend half an hour a week on the phone trying to resolve these type of issues. But it comes out to be 3-4K MQMs/ month so its worth it.