This happened to me about 3 years ago. Phone booking with 2 Amex vouchers for 4 people. Flight showed as a cash flight in terms of Avios..it never changed even after ticketing. We received full Avios & TPs (and even more when another 20k pp was proactively given due to a service failure in J). Was the best value flight I've ever had. I did mention it once to a phone agent and they said to leave it.