老师,您好,我遇到了如下问题,也不知道是哪里错了,检测了一天,没有找到原因,望您指教.谢谢

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Graphs.Edge.WakeUp () (at <9b4f11af421247d4a580ece51f55f278>:0)
UnityEditor.Graphs.Graph.DoWakeUpEdges (System.Collections.Generic.List`1[T] inEdges, System.Collections.Generic.List`1[T] ok, System.Collections.Generic.List`1[T] error, System.Boolean inEdgesUsedToBeValid) (at <9b4f11af421247d4a580ece51f55f278>:0)
UnityEditor.Graphs.Graph.WakeUpEdges (System.Boolean clearSlotEdges) (at <9b4f11af421247d4a580ece51f55f278>:0)
UnityEditor.Graphs.Graph.WakeUp (System.Boolean force) (at <9b4f11af421247d4a580ece51f55f278>:0)
UnityEditor.Graphs.Graph.WakeUp () (at <9b4f11af421247d4a580ece51f55f278>:0)
UnityEditor.Graphs.Graph.OnEnable () (at