“NullReferenceException” errors are spammed in the Console and Project Settings window becomes unusable after installing the AI package with Project Settings docked

Steps to reproduce:
1. Create new Unity project using Universal 3D Project
2. Open Project Settings window and dock it next to Game tab
3. In the Unity toolbar, click the “AI” button
4. Click “Agree and install Unity AI” and install AI Package
5. Once AI package is installed, observe the console window

Actual results: “NullReferenceException” errors are being spammed in the Console window, Project Settings window is unusable

Expected results: No errors are thrown in the Console, Project Settings window is usable

Reproducible with versions: 6000.3.15f1, 6000.4.7f1, 6000.5.0b8, 6000.6.0a4
Can’t test with versions: 6000.0.75f1 (AI Assistant package is not available)

Tested on (OS): Windows 11 (Reproducible), macOS Tahoe 26.4.1 (Not reproducible)