It is most likely an issue with the occupant sensor. I am not familiar with the Ford design, but there a many types. Some a mats placed between the cushion pad and suspension, some on top of the pad, and some a strain gages located on the seat tracks. All are meant to read a change in mass on the seat and adjust the airbag deployment time, or activate the airbag if it is a single stage. Broken lift mechanism will change the load path and distribution, which would cause this fault. Also some seat tracks have position sensors in combination with a weight sensor, this can further revise airbag deployment timing. This could be a latent error (told to store or always stay on) and a reflash may resolve the issue. Otherwise there could be damage to the mass sensor itself.
I just have not looked in a while, and don't have my contacts to that seat product anymore, but hopefully this helps a bit.