How to reproduce:
1. Create a new Unity project 
2. Create any VFX Graph and open it
3. Press the "Space" key in any open space to open the Node creation menu
4. Navigate to the folders and quickly click on them to expand and collapse them
5. Observe the Console

Expected results: No errors are thrown
Actual results: NullReferenceException is thrown

Reproducible with: 6000.0.50f1, 6000.1.5f1, 6000.2.0b3

Reproducible on: macOS Sequoia 15.4 (M1)
Not reproducible on: No other environment tested

First lines of the error:
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.VFX.UI.VFXView.AddNode (UnityEditor.VFX.Variant variant, UnityEngine.Vector2 mPos) (at ./Library/PackageCache/com.unity.visualeffectgraph@e07c4c789cd8/Editor/GraphView/Views/VFXView.cs:478)
UnityEditor.VFX.UI.VFXView.<ConnectController>b__20_1 (UnityEditor.VFX.Variant d, UnityEngine.Vector2 mPos) (at ./Library/PackageCache/com.unity.visualeffectgraph@e07c4c789cd8/Editor/GraphView/Views/VFXView.cs:308)