I wonder if the AF system queried your status when you booked the ticket and then never pinged DL again to dynamically update it after
From my experience, this is what happens with the AF/KLM booking system: the status is tagged to the reservation at the time of ticket purchase (or at the time you first enter your frequent flier number), and sticks.
you can get all the benefits by showing your current status confirmation on the day you fly.