Check at runtime if the property has value. If not it wont run. Check how to trace a agent and try tracing the sla agent on its next run, so as to understand if the clipboard has the value when SLA runs
As you mentioned that Get DateTime From where you referred X property whether it is an datetime property or only a date property?
System uses the value of this property to compute the deadline time (property Work-.pySLADeadline) and goal time (property Work-.pySLAGoal) for the assignment only once, when the assignment is created.
Later changes to the value of this property do not automatically cause any recomputation of these times.
Reference a property with a DateTime type here; you cannot use Date properties.