conditional fields logic not work

hello
I create 2 dropdown fields F! is role dropdown and F2 is new dropdown field
I made conditional logic for F2 to be appear when the value of F1 equal to member

when I opened the registration form page and I choose F! = member F2 didn’t appear

I thought this bug from one of plugins or theme so I disable all plugins and I change theme to be twenty sixteen but the bug still there

so please tell me how to fix this bug
thank you