How to reproduce:
1. Open the user’s attached “UIToolkit_2022.3_Test.zip” project
2. Open “SampleScene” Scene (Assets > Scenes)
3. In the Hierarchy window, select “EXAMPLE” GameObject
4. Observe the “UITK Class” Component in the Inspector window

Expected result: Gradient shows alpha as checkboard
Actual result: Gradient doesn’t show alpha as checkboard

Reproducible with: 2022.2.0a9, 2022.21f1, 2022.3.17f1, 2023.2.7f1, 2023.3.0b4
Not reproducible with: 2021.3.34f1, 2022.2.0a8

Reproduced on: macOS 13.6.3 (Intel)
Not reproducible on: No other environment tested

Note: not reproducible with IMGUI