NullReferenceException error is thrown on renaming properties in blackboard window at the time creating a property.

Steps to repro:
1. Create a new HDRP project.
2. Project window > Click on "+" > Shader > HDRP > Unlit Shader Graph.
3. Open Shader Graph > Blackboard Window.
4. Add Vector1 property > Rename > Enter.

Actual Result:
NullReferenceException error in the console.

Expected Result:
No error in the console.

Reproducible in:
2020.2.0b3, 2020.2.0a20 with Package Version 10.0.0-preview.27.

Working Fine in:
2020.2.0b3, 2020.1.6f1 with Package Version 9.0.0-preview-54, 8.2.0.

Environment:
Occurring on Windows 10 & Mac 10.15.

Stacktrace:
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.ShaderGraph.Drawing.BlackboardFieldView.InspectorUpdateTrigger () (at Library/PackageCache/com.unity.shadergraph@10.0.0-preview.27/Editor/Drawing/Blackboard/BlackboardFieldView.cs:91)
UnityEditor.ShaderGraph.Drawing.BlackboardProvider.EditTextRequested (UnityEditor.Experimental.GraphView.Blackboard blackboard, UnityEngine.UIElements.VisualElement visualElement, System.String newText) (at Library/PackageCache/com.unity.shadergraph@10.0.0-preview.27/Editor/Drawing/Blackboard/BlackboardProvider.cs:259)
UnityEditor.Experimental.GraphView.BlackboardField.OnEditTextFinished () (at <f3cbee11fcf24e738f9a6216ec699f5c>:0)
UnityEditor.Experimental.GraphView.BlackboardField.<.ctor>b__20_0 (UnityEngine.UIElements.FocusOutEvent e) (at <f3cbee11fcf24e738f9a6216ec699f5c>:0)
UnityEngine.UIElements.EventCallbackFunctor`1[TEventType].Invoke (UnityEngine.UIElements.EventBase evt) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventCallbackRegistry.InvokeCallbacks (UnityEngine.UIElements.EventBase evt) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.CallbackEventHandler.HandleEvent (UnityEngine.UIElements.EventBase evt) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventDispatchUtilities.PropagateEvent (UnityEngine.UIElements.EventBase evt) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.DefaultDispatchingStrategy.DispatchEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventDispatcher.ApplyDispatchingStrategies (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, System.Boolean imguiEventIsInitiallyUsed) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventDispatcher.ProcessEventQueue () (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventDispatcher.OpenGate () (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventDispatcherGate.Dispose () (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.EventDispatcher.Dispatch (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, UnityEngine.UIElements.DispatchMode dispatchMode) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.BaseVisualElementPanel.SendEvent (UnityEngine.UIElements.EventBase e, UnityEngine.UIElements.DispatchMode dispatchMode) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.UIElementsUtility.DoDispatch (UnityEngine.UIElements.BaseVisualElementPanel panel) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.UIElementsUtility.UnityEngine.UIElements.IUIElementsUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& eventHandled) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.UIEventRegistration.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.UIElements.UIEventRegistration+<>c.<.cctor>b__1_2 (System.Int32 i, System.IntPtr ptr) (at <25b3b10f7ceb493e97ab16f983c3ca81>:0)
UnityEngine.GUIUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& result) (at <931b26b61f444e3485195721b0227b20>:0)