Versions tested: 21.2.0f1 & 22.1.0a15 (trunk)

Steps:
Open a new projects and create a simple scene (plane box and a sphere)
Create a new material and assign to the sphere
In the material, change it to transparent and change the refraction modes
Test Box, Sphere and Thin refraction modes

Hapenning:
Box and Thin modes doesn't work, Sphere mdoe works
(comparison with doc results: https://docs.unity3d.com/Packages/com.unity.render-pipelines.high-definition@7.1/manual/Refraction-in-HDRP.html )

Expected: It works

Note: Doesn't work either with a SG