Hi Bill - So the good news is, your control is correctly wired if you can turn it on and off from the PD-6ANS. I want to go over pairing and factory defaulting.
Pairing: You stated that you have 7 other Caseta Dimmers, and having an extender switch. Are you using the Caseta Wireless Smart Hub? Have you tried adding in the PD-6ANS and the Pico remote into the Lutron App?
Factory Defaulting: Please try following these steps in the video linked below. This video shows a Dimmer but the same procedure will apply for a PD-6ANS.
https://www.youtube.com/watch?v=foHMG1e_F5Q. When you follow these steps if you have any issues please let us know how far you were able to make it in the video. (E.g. got first set of flashes, but did not get the 2nd set of flashes)