Steps to reproduce:

1. Create a new Unity project using a 3D Universal Template
2. Go to Edit > Project Settings > UI Toolkit
3. Enable "Advanced Text Generator"
4. Create a UI Document (Assets > Create > UI Toolkit > UI Document (UXML))
5. Double-click on it to open in UI Builder
6. Drag a Label to the UI Builder Hierarchy and select it
7. In the Inspector, expand the "Text" foldout
8. Change "Text Generator Type" to Advanced
9. Enable "Auto Size" property
10. Click File > Save
11. Resize the Inspector panel in the UI Builder
12. Observe the Console

Actual results: "Underline vertex left position is greater than right position" and "Underline start position is greater than end position" errors are spammed in the Console

Expected results: no errors

Reproducible with versions: 6000.4.0b5

Not reproducible with versions: 6000.0.66f1, 6000.3.5f1, 6000.4.0b4, 6000.5.0a5

Tested on (OS): Windows 11

Notes:

• Not sure of the exact repro steps, as it can be quite inconsistent, and the issue has reproduced without performing all the steps. But the provided steps should reproduce the issue