It is working, randomly. We booked a FN with 35K Chase cert, from the Cert itself.
The option to use the certs are available in the booking screen, but because of the recent reported glitch, I chose to go from the cert itself, because I also wanted to make sure the correct cert is being used (the Chase cert expires in first week of June while the AMEX cert expires in Dec).
I figured by going directly from the Cert itself, there would not be any chance for the system to use a different cert. It worked as expected. knock on wood!
Reservation does show This Reservation has eCert. Account has very little points in it anyway so no way for the system to deduct any pts.