mastery paths can't start on discussions?

[Seangt]

I'm testing out mastery paths just to see how they work. I can get it to work fine if I start on an assignment or a quiz, but every time I try to set it up where I add the conditionals onto a graded discussion as the start, I click save on the mastery paths screen, and nothing is saved. In the module there's no indication mastery paths is in use, and if I go back to the mastery paths page the setup is gone. I am clicking Save. There is no error. Is this normal?