I am trying to update the "Due date" field within a created issue. The created issues are for the review of our Vendors. We have an object type called "Vendors" where all Vendors are stored. The created issue's "Due date" should be based off of the "Next Performance Review Date" attribute stored within each Vendor object. 
You can see below, the automation checks our defined criticality of the vendor and depending on the criticality and the next performance review date, the due date is determined. To me the smart value makes sense, but every-time I run the automation it completes successfully but the due date is not updated within the issue.