ntfs partition is reported via the "mount" command, among others. So this is an NTFS file system that you're writing to? I think that's got to be related to your problems somehow. Maybe you're exceeding some limit in the Linux NTFS driver (single file size, total capacity, who knows).
yes, format with ext4 or btrfs or ...
you know parted`?
https://gparted.org/livecd.php
Greets
Stefan