I solved it! Never been more proud of a simple answer…
When specifying the path of your Python installation (in the “Python Scope” activity), make sure to use double backslashes to escape the first one.
So instead of:
“C:\Users\username\AppData\Local\Programs\Python\Python36”
you actually need to do…
“C:\\Users\\username\\AppData\\Local\\Programs\\Python\\Python36”