FCPX Tape Archive and Import Problem

I am attempting to Archive or Import HDV video to FCPX. The hardware is a Sony professional tape deck with firewire. The connection to my M1 MacPro laptop is via a firewire to USB cable, an Apple USB to Thunderbolt 1 adapter, connected to an Apple Thunderbolt1 to USB C adapter running into one of the USB C laptop inputs! Amazingly this works to a degree with the laptop able to control the tape deck and see and import the tape data if and only if the data is imported a clips of a few minutes or less. When I attempt to either Archive or Import the entire contents of a 50 minute tape (which contains only one video break between halves or a recital), the result if hundreds of 1 second or less clips that in sum only contain about one fourth of the tape's data. The laptop has 16 Gig of memory and a Terabyte of storage with plenty of space for the data. I have 200 of these tapes that I want to process! While importing, the video is displayed flawlessly on both the Mac and an HD monitor connected to the deck.