Question about what happens with cancelled TB funds that may have been answered but I didn't see (feel free to point me in the correct direction if so, sorry!).

I have a flight in February that I want to book w/ points close in, but in case there is no availability close in, I'd like to have a flight on the books ahead of time. I know if I book w/ credit card and cancel, I'll get FFC that expire in 1 year, which might not be enough time for me to utilize all the FFC. What happens if I buy Travel bank funds to use to buy my flight (not a fully refundable fare), and then cancel > 24 hrs after reservation - seems like those funds would still go to FFC that expires in 1 year rather than back to Travel bank with expiration in 5 years?