Whenever I attempt to copy a card in-camera from Slot 1 (shot content) to Slot 2 (formatted, empty), the progress bar chugs along nicely until it reaches 95% and then just stops. Both slots still blink amber. Screen remains the same: "NOW COPYING. DO NOT OPEN THE CARD DOOR." I've waited it out for about 10 minutes. No change.
Just be patient. How big is your card? I have the same experience where progress bar quickly jumps to 95% completed and then just hangs for maybe 10min for a full 16gb card- never timed it but it felt like 10min.
But then it finishes and all is fine. Not fast but a terrific underrated feature of the af100. I often give the client exposed cards after copying them first for safety. Also allowing copying of select clips is fantastic.