The Corrective Action record contains two different due dates which is confusing: Due dates for the actions in the Action Details table and the overall Due Date in the Details stage.
It is not clear however what the function of the the latter due date is because to me it would seem that the due date for the actions is the due date of the entire record.
So to clarify the situation the Due Date field could perhaps be named Due Date for Investigation & RCA. This would mean that the workflow is much clearer when you open CAPAs from other records and assign responsibility of the record to someone else.
Also, you might consider adding a due date field for Review, because sometimes there can be even a year between the action and review of the effectiveness.