Both rounded corner scripts stop working in the built application (Windows, Unity 2021.3.0f1)

[PuFGGs]

When I used corner scripts in prefabs and Instantiate prefab in built runtime occurs an error and won't work. (It always works in the editor without any errors.)

[davide-aldegheri]

Hey, I had this issue too, the problem is that in both RoundedCorners scripts use Shader.Find("UI/RoundedCorners/RoundedCorners") and Shader.Find("UI/RoundedCorners/IndependentRoundedCorners")
which can't work in a build, a workaround is to go into Project Settings -> Graphics -> Always Include Shaders, increment the value by 2 and add both shaders you can find inside Packages.

It would be nice if there was a script on load that automatically adds those but you can solve it simply by doing that