If the revision is to check "Evaluate 'Not Set' as false" on the loop, that's how it's supposed to be set up.
I should have mentioned that, as for some reason a variable doesn't equal itself if it's null(it's a boolean with both "Variable Name" and "Another Variable" set to the exact same thing).
You could just use the boolean variable to run and terminate the loop instead of the "Loop Break" action, if you prefer.