Whenever I try to open the string picker via a "Challenge Status" or "Dealer Dice" action, unity gives me the following error:

NullReferenceException: Object reference not set to an instance of an object
Defiant.Modding.StringLink.OpenStringPicker (Defiant.Modding.StringLink a_stringLink, Defiant.Modding.StringLibrary a_lib, UnityEngine.Object a_baseObject)
Defiant.Modding.StringLink.Draw (System.String a_label, Defiant.Modding.StringLink a_stringLink, Defiant.Modding.StringLibrary a_lib, UnityEngine.Object a_baseObject)
Defiant.Modding.ChallengeStatusTask.OnTaskInspectorGUI ()
Defiant.Modding.NodeCanvas.Framework.Task.ShowTaskInspectorGUI (Defiant.Modding.NodeCanvas.Framework.Task task, System.Action`1 callback, Boolean showTitlebar)
Defiant.Modding.ParadoxNotion.Design.EditorUtils.TaskField (Defiant.Modding.NodeCanvas.Framework.Task task, Defiant.Modding.NodeCanvas.Framework.Node node, ITaskSystem ownerSystem, System.Type baseType, System.Type agentType, System.Action`1 callback)
Defiant.Modding.NodeCanvas.Framework.Node.TaskAssignableGUI ()
Defiant.Modding.NodeCanvas.Framework.Node.ShowNodeInspectorGUI ()
Defiant.Modding.NodeCanvas.Framework.Graph.ShowInspectorGUIPanel ()
Defiant.Modding.NodeCanvas.Framework.Graph.ShowGraphControls (UnityEngine.Event e, Vector2 canvasMousePos)
Defiant.Modding.NodeCanvas.Editor.GraphEditor.OnGUI ()
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:285)
UnityEditor.HostView.Invoke (System.String methodName) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:278)
UnityEditor.HostView.InvokeOnGUI (Rect onGUIPosition) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:245)