We have confirmed this is working, we tested this on a iMac 27" 5K running Mac OS X 10.13.6 and Pro Tools 2019.6.
- Open the menu Setup - > Peripherals - > MIDI Controllers Tab
- Drop down option for Type - Select "None" to clear the preference - numbered slot #1, #2, #3 or #4 (whichever has your FaderPort listed)
- Open same Drop down for Type and select "HUI"
- Under "Receive From" and "Send To" select - > Predefined - > FaderPort
- # Ch's should be 8
- Click OK
If that doesn't work, you'll need to clear your Preferences for Pro Tools and try and again. To clear your Pro Tools preferences in your OS contact read this article from Sweetwater or Contact Avid Tech Support for more assistance.