Trying to SFTP into the RPi board with a local ethernet connection on either the root or mind accounts resulted in an immediate Connection closed from the server.
I got it to work by editing the /etc/ssh/sshd_config and /etc/ssh/sshd_config_readonly files to change the line that read
Subsystem sftp /usr/libexec/sftp-server
Subsystem sftp internal-sftp
I don’t know if this is the preferred fix, but it does work for getting sftp access for now. I can add the issue to GitHub if you would like me too.