Redwood promote grade field

Summary:

We are planning on enabling the Redwood version of the promote process. Everything works fine but we just had an issue with the grade field. When we use person management or the current promote process, based on the job we select the grades tied to that job show up. In the new Redwood promote design all of the grades show up. If we select a grade that isn't in the job then we get an error message saying "Couldn't change the assignment. Null". But if we select a grade that matches that job then we are allowed to continue or