Evan,
I have the same problem. The custom font pack uploads, unpacks and installs correctly, giving me the same success message OP posted but does not display the font preview as it does in your videos. I looked in the wp-svg-icons folder and it does in fact contain the icon font in wp-svg-icons\custom-pack\fonts. Everything in those folders is permed rw-r–r–. This is on an OpenShift PAAS installation.
