Reproduction steps:
1. Open the attached “repro_IN-91640“ project
2. Open the “Assets/Scenes/SampleScene.unity“ Scene
3. Select the “Assets/CompilationTest.shadergraph“ Shader
4. In the Inspector, press “View Generated Shader“
5. In the opened “GeneratedFromGraph-CompilationTest.shader“, search for “struct VertexDescription“
6. Once found, notice that it consists of two “half3“ values and one “float3“ value
7. Back in the Editor, open the “Assets/CompilationTest.shadergraph“ Shader
8. Hover over the “Vertex“ node and press the right mouse button, then select “Add Block Node → Tangent“
9. Save the edited shader graph (“Ctrl + S“)
10. Repeat the 4th and the 5th steps
11. Once found, observe what the method consists of

Expected result: “VertexDescription” method consists of two “half3” and one “float3” value
Actual result: “VertexDescription” method consists of three “half3” values

Reproducible with: 2021.3.47f1, 2022.3.55f1, 6000.0.33f1, 6000.1.0b1

Reproducible on: Windows 10 (22H2), Windows 11 (23H2)
Not reproducible on: No other environments tested