Reproduction steps:
1. Open the attached “BugRepro” project
2. Open the “Assets/UI/MainMenu“ Visual Tree Asset using the UI Builder
3. In the UI Builder window Hierarchy tab, select “Container > SinglePlayerMenu > GameCreationMenu >Horizontal > SettingsWindow > GameSettings > unity-tab-view__content-container > Factions > unity-tab_content-container > FactionList” visual element
4. In the Inspector tab, observe the selected Item Template setting
5. In the Viewport tab, press “Preview”
6. Select the “$FactionSettings“ tab
7. Press the plus sign to add an element to the list
8. Observe the Console

Expected result: No errors are logged and a visual element with the selected Item Template appears
Actual result: “NullReferenceException” error is logged and no visual element appears

Reproducible with: 6000.0.25f1, 6000.1.0a2
Not reproducible with: 2021.3.45f1, 2022.3.51f1 (The “MainMenu” Visual Tree Asset broke due to unknown visual element types)

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Note: To easier see the “NullReferenceException” error, clear the Console before step 7