There have been reports of those certs not automatically redeposited after canceling a reservation made with such certs. I have experienced that myself, too. At least one person here has reported success with a work around where one would need to detach the cert from an unwanted reservation prior to cancellation. If the cert doesn't get redeposited automatically, then it will require a call to have it manually put back into your account.
LAX
Thanks for giving your DP. Did you get an email relating to the redeposit of your FNA into your account? The reason I am wondering, is like I said, around the time I manually called to cancel my reservation and get my FNA redeposited, I got an email saying that I had gotten a new annual FNA from my CC. At first I thought the email was just notification that my FNA had been redeposited, but then I looked closer at the email I had received, it was identical to the one I got last year when I got my annual FNA, so I wasn't sure if I had actually gotten my cancelled FNA back, or gotten my new one from the CC.