A random harmless warning on EVERY versions.

Hello? Can someone explain me what it is? It goes away for a while when I restart the edit but comes back inevitably. The magical thing about it is that I’ve seen this error in every versions 2019.x 2018.x 2017.x

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Graphs.Edge.WakeUp () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Edge.cs:114)
UnityEditor.Graphs.Graph.DoWakeUpEdges (System.Collections.Generic.List1[T] inEdges, System.Collections.Generic.List1[T] ok, System.Collections.Generic.List`1[T] error, System.Boolean inEdgesUsedToBeValid) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:387)
UnityEditor.Graphs.Graph.WakeUpEdges (System.Boolean clearSlotEdges) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:286)
UnityEditor.Graphs.Graph.WakeUp (System.Boolean force) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:272)
UnityEditor.Graphs.Graph.WakeUp () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:250)
UnityEditor.Graphs.Graph.OnEnable () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:245)

I have the same error, did you manage to find out the reason?