Seems not working in Unity 2021.2.9f1c1

[buger404]

How I used it:

I used 'Light2D' in my project(URP), and I had fixed the errors in materials(missing shader), attaching the script 'SuperBlur' to the MainCamera and attached the two materials as well.
also I changed the settings following the screenhost in README, then I added a UI Image, setting its material to 'SuperBlurUI', but it didn't work.

How it didn't work:

It kept its original apperance(a whole white image).
plus I managed to edit the shader code return half4(bgcolor, 1.0);, the color of the image changed.

was there something wrong when I used it or is it a potential bug?