Within an Application, a user is clicking the International checkbox, however the Fee Rule for this International is not applying to the Application.
The more than likely cause of this is that the Fee Rule amount exceeds the Application Fee amount. Currently, the System only applies the lowest fee amount to the Application. For example your school has a Application fee of $100.00, you also have a Rule set up for $200.00 for International Students (which exceeds the original Application fee amount of $100.00), this does not work because the $200.00 fee rule is higher than the $100.00 Application Fee.
We are going to see if this is something that can be changed in the future, however until that time, it is best to have a separate International Application with the Application Fee ($200.00 as per above example) entered for International Students.