Reproduction steps:
1. Open the attached “IN-91495.zip” project
2. Open Assets > Scripts > BugUITKInheritance.uss
3. Open Assets > Scripts > BugUITKInheritance.uxml in UI Builder
4. Observe the column on the right
Expected result: The column text color is red
Actual result: The column text color is black
Reproducible with: 6000.0.37f1, 6000.1.0b5, 6000.2.0a2
Couldn’t test with: 2022.3.57f1 (“error CS0246: The type or namespace name 'UxmlElementAttribute'“ and “error CS0246: The type or namespace name 'UxmlElement'“ errors)
Reproducible on: Windows 11
Not reproducible on: No other environment tested