Shader Graph Main Preview color is not updated when modifying the Base Color node in UI Shader Graph

Steps to reproduce:

1. Create a new project using Universal 3D template
2. Go to Assets > Create > Shader Graph > URP > UI Shader Graph and open it
3. Click on the color field next to Base Color node
4. Change it to any other color
5. Observe the Main Preview

Actual results: The color in the Main Preview does not change

Expected results: The color in the Main Preview changes immediately to reflect the new Base Color

Reproducible with versions: 6000.4.1f1 (8535861f39e1), 6000.5.0b2, 6000.6.0a2

Not reproducible with versions: 6000.3.12f1, 6000.4.0f1 (8cf496087c8f)

Tested on (OS): Window 11

Notes:

• The color correctly updates in the preview only after saving and reopening the Shader Graph window