Default Shader Graph in the VFX Graph Output block can't be reselected when switched to the custom Shader Graph

How to reproduce:
1. Open the attached project "DefaultBug"
2. Create any VFX Graph
3. In the VFX Graph, create the "Output Particle Shader Graph" block
4. Navigate to the "Shader Graph" field, open the selector and observe the results
5. Select the "New Shader Graph"
6. Reopen the selector and observe the results

Expected results: The same amount of Shader Graphs is available in both cases (custom and default ones)
Actual results: After selecting the custom Shader Graph, all default ones can't be selected

Reproducible with: 6000.3.0b7, 6000.4.0a3
Can't test with: 6000.0.60f1, 6000.2.8f1 (No default assets)

Reproducible on: macOS Sequoia 15.6 (M1)
Not reproducible on: No other environment tested