EndLayoutGroup: BeginLayoutGroup error on saving shader graph using Save As.

Steps to repro:
1. Create a new HDRP template project.
2. Project Window > Click on "+" > Shader > PBR Graph.
3. Open Newly Created Shader Graph > Add Vector1 Property > Save.
4. Click on "Save As" button > Save > Click on Yes.
5. Repeat step 4.

Actual Result:
EndLayoutGroup: BeginLayoutGroup error is in the console.

Expected Result:
No error in the console.

Reproducible in:
2020.2.0a14, 2020.2.0a12 with Package Version 9.0.0, 8.1.0.

Working Fine in:
2020.2.0a11, 2020.1.0a23 with Package version 8.0.1.

Environment:
Occurring only on Windows.

Stacktrace:
EndLayoutGroup: BeginLayoutGroup must be called first.
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)