Tyler-

You want to inspect the first line of the dcm2niix output
  Chris Rorden's dcm2niiX version v1.0.20210410 Clang12.0.0 ARM (64-bit MacOS)
and make sure you are using the latest stable release (v1.0.20210317)
  https://github.com/rordenlab/dcm2niix/releases
I note that the sequence is called 4D but the software thinks there are only 3 dimensions (336x336x1108x1). My best guess would be that an anonymization stage removed some of the critical spatial meta data from this scan. Is the problem resolved if you export the data directly off the scanner?