Spline.SetKnot creates a subscriber leak when the Scene tab is closed or not visible

How to reproduce:
1. Open the attached “SplineBug” project
2. Open “scene” scene
3. Close the Scene tab
4. Navigate to Window > Analysis > SceneView Debugger
5. Enter Play mode
6. Observe the SceneView Debugger window

Actual result: The count of subscribers in SceneView.duringSceneGui exponentially increases
Expected result: SceneView Debugger window displays "No subscribers found (List is null)" 

Reproducible with: 2.8.2 (6000.0.65f1, 6000.3.4f1, 6000.4.0b4, 6000.5.0a4)
Not reproducible with: 2.8.1 (6000.0.65f1, 6000.3.4f1, 6000.4.0b4, 6000.5.0a4)

Reproducible on: Windows 11, macOS 15.7.2 
Not reproducible on: No other environments tested