Reproduction steps:
1. Open the “ReproProject“ project
2. Open the “Assets/Scenes/SampleScene“ scene
3. Open the “Assets/ShaderGraphs/ShaderGraph_Vegetation_Wind_Lit“ ShaderGraph
4. Delete the connection to the SpriteColor Node in Fragment
5. Save the ShaderGraph
6. Reconnect the Combine Node to the SpriteColor Node in Fragment
7. Repeat step 5
8. Observe the Game View

Expected result: There is a grass texture on the plane
Actual result: The plane is gray

Reproducible with: 2021.3.38f1, 2022.3.28f1, 6000.0.3f1

Reproducible on: Windows 11 Pro (22H2)
Not reproducible on: No other environment tested

Notes:
1. Adding Base Color Node to Fragment does not work and nothing happens
2. Closing the Shader Graph window and reopening the “Assets/ShaderGraphs/ShaderGraph_Vegetation_Wind_Lit“ ShaderGraph results in a Base Color Node appearing in Fragment and the SpriteColor Node becomes grayed out