How to reproduce:

1. Open the “ATGBug.zip“ project
2. Open the “Assets/Data/UI Toolkit/NewUXMLTemplate.uxml“ in UI Builder
3. Select the “text-ParagraphSpacing“ element in the UI Builder’s Hierarchy
4. In the UI Builder’s Inspector, change the Text → Paragraph Spacing value
5. Observe the UI Builder’s Viewport

Alternatively:

1. Open the “ATGBug.zip“ project
2. Open the “Assets/Data/UI Toolkit/NewUXMLTemplate.uxml“ in UI Builder
3. Select the “text-LineHeightRichText“ element in the UI Builder’s Hierarchy
4. In the UI Builder’s Inspector, change the percentage in the ‘line-height’ tag of the Text field
5. Observe the UI Builder’s Viewport

Actual results: Nothing happens
Expected results: Changes reflect on the text displayed in the Viewport (spacing between lines gets bigger/smaller)

Reproducible in: 6000.0.23f1, 6000.0.66f1, 6000.3.4f1, 6000.4.0b4, 6000.5.0a4
Could not test in: 6000.0.0f1 (Unreliable testing due to different behavior)

Reproduced on: Windows 11 Pro (25H2)
Not reproduced on: No other environment tested

Notes:
- Advanced Text Generation has to be enabled both in the Project Settings → UI Toolkit and in the UI Builder on each document under the Text section
- In 6000.0.0f1, the ‘line-height’ tag is not working, and paragraph spacing only works after the last paragraph. Such results make the results unreliable