How to reproduce:
1. Open the attached “IN-96240_Material Keyword Reproduction” project
2. Open the Project window, navigate to the “Shader” ShaderGraph and open it
3. Navigate to the “Shader” ShaderGraph window and duplicate the existing Boolean keyword
4. Drag the duplicated Boolean keyboard to ShaderGraph Blackboard
5. Connect the duplicated Boolean keyword’s “Out(1)” node to the “Tangent(3)”, “Normal(3)”, or “Position(3)” output in the Vertex Output
6. Ensure no GameObjects are selected in the Inspector, then save the shader file
7. Go to File > Save Project to save the changes
8. Open the corresponding Mat.mat file in a text editor and observe the population of {{m_ValidKeywords:}} list

Expected Results: The Mat.mat file is updated immediately after saving the “Shader” ShaderGraph
Actual Results: The Mat.mat file is not updated immediately after saving the “Shader“ ShaderGraph

Reproducible with: 2021.3.50f1, 2022.1.0a1, 2022.3.60f1, 6000.0.43f1, 6000.1.0b11, 6000.2.0a7

Reproducible on: MacOS 15.3.1 (M1 Max)
Not reproducible on: No other environments tested

Workarounds: If you go to the project again and navigate to Scene View and then save the project, you can populate the {{m_ValidKeywords:}} with duplicate Boolean Keyboard