Distro ISO EFI Installation Drive Partitioning Error

We need the ability to install on a particular drive in a multi-drive system - when we do this via an advanced install, Anaconda blows up with a fatal error that only lets us reboot the system.

Steps to reproduce:

1. Boot from ISO as EFI
2. Select FreePBX 14 Advanced Installation
3. Select Advanced Installation with Normal Video
4. Select Advanced Install with Asterisk 13 via Standard Video
5. Go into the disk selection screen, select the disk you want to install to, and click the blue Done button
6. Fatal error "An unknown error has occurred", and proceeds to give some errors and the contents of the kickstart file and related files.

It should be fairly easy to reproduce, but I can try to grab the information that is provided in the logs if necessary.