Symptoms
Customer used K2 smart forms for editing a SharePoint List Item and placed a "Update List Item" Method on a custom view. When running the Form and clicking "Update List Item" control, the customer was getting an error saying that "ID field is required to update a list Item".
Diagnoses
The wrong items from the Context Browser were being pulled into the Input Mapping screen
Resolution
In the Input Mappings, populate the fields with the corresponding SmartForm Controls instead of the properties of the specific SmartObject.