If a Booking.com reservation was made through their Risk-Free Reservations Program, even though the guest may have cancelled, the reservation is still active. Booking.com don't mark this reservation as cancelled and so it remains on Uplisting.
What happens when a guest cancels a Risk-Free Reservation?
This means the original reservation (technically cancelled now) will remain active on the system, with the tag 'Risk-Free' internally on the Extranet's Reservations tab and the property will receive a virtual credit card to charge for the cost.
On your Booking.com Extranet Reservations tab, you can check the reservation status as shown below. The status for this reservation is "Looking for replacement guest(s)".
For more information, you can take a look at these articles in Booking.com's Partner Help Centre: