System Information
Operating system: Windows 10 May 2021 Update
Graphics card: tested in rtx 3060 ti and gtx 1060

Blender Version
Broken: Blender 3.0 Cycles-X branch 22/09/2021 (and older Cycles-X versions)
Worked: Not Cycles-X versions

Short description of error
I think there is a problem with transparent objects and SSS (both “fixed radius” and normal random walk), when you use a transparent object on top of an object with SSS there is a strange effect in which you can still see the shape of the object.
Video example:
https://youtu.be/RYQzz4JwgQ4

Exact steps for others to reproduce the error

1. add Principled BSDF to an object
2. add the color/texture to base color and subsurface color
3. raise the value of subsurface to any value above 0 (with fixed radius or normal random walk)
4. add another object only with a transparent shader on top of the object.

Example .blend