How to reproduce:
1. Create a new Unity project
2. In the Project window, right-click -> Create -> Shader Graph -> Any Shader Graph
3. In the Shader Graph Editor, Create Node -> Custom Function
4. Move the node and observe the results

Expected results: Moving the node doesn't affect the preview
Actual results: The node is created expanded and empty and then becomes shrunk when moved

Reproducible with: 6000.1.0b7, 6000.1.1f1, 6000.2.0a9
Not reproducible with: 6000.0.48f1, 6000.1.0b6

Reproducible on: Windows 11 Pro, macOS Sequoia 15.3 (M1)
Not reproducible on: No other environment tested