Crash on PPtr<Shader>::operator Shader*() const when Calling Resources.UnloadUnusedAssets() in a specific project

How to reproduce:
1. Open the attached “CrashRepro“ project
2. Open the “Scriptable Sheets” window (Window>Scriptable Sheets)
3. Select “Alpha Merge“ in the Shader list (or any other Shader)
4. In the Inspector, press “Open in Shader Editor“
5. Close the “Shader Editor” window by pressing the “x“ button at the top left of the window (top right if Windows)

Reproducible with: 6000.0.57f1, 6000.2.4f1, 6000.3.0b2

Reproducible on: macOS 15.6.1 Sequoia (Intel), Windows 10 (by user)
Not reproducible on: No other environment tested

Note: if commenting out line 1057 in the “Assets/AmplifyShaderEditor/Plugins/Editor/Menu/AmplifyShaderEditorWindow.cs“ Script, the issue no longer reproduces

First few lines of the stack trace:
0x00007FFBA65575DF (Unity) PPtr<Shader>::operator Shader * __ptr64
0x00007FFBA6B09FAD (Unity) Material::GetShader
0x00007FFBA728F2CD (Unity) GUIStyle::RenderText
0x00007FFBA728BBE5 (Unity) GUIStyle::DrawContent
0x00007FFBA60F07E1 (Unity) GUIStyle_CUSTOM_Internal_DrawContent