Sony RDR-VX410 - won't record all

Hi. I’ve a Camcorder and a Sony RDR-VX410. In the past I’ve had no problem transferring my camcorder tapes to DVD using the recorder. I’ve just tried (twice) to copy a one-hour video over and, both time, the first 4 minutes 48 seconds is missing when I pay back the DVD. I tried recording just the first 4 minutes 40 seconds as a separate recording - and it shows on the menu of the completed DVD, but won’t play back. Does anyone have any suggestions? I guess that I could record it to a VHS tape and then transfer that to the DVD - and hope that that would work…
Thanks