cannot select python version during configure of Paraview 5.8 (and master)

I have multiple versions of python installed on my Mac via Macports. When running ccmake with Parview 5.8, my selections for:

Python3_LIBRARY_RELEASE
_Python3_EXECUTABLE
_Python3_INCLUDE_DIR
_Python3_LIBRARY_RELEASE

Are all ignored. I am trying to select python-3.6 (/opt/local/bin/python3.6), but python-3.8 (also Macports) is always populated after running configure. I also tried the master branch and my selections are again ignored (interestingly, Xcode python-3.7 is found instead).

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information