SubSurface material problems

The subsurface material looks awesome, BUT why does the shadows totally darken the opossite side? Its kinda useless to have a good looking subsurface material but cant use it when casting shadows.

The expected material luminosity:

0fca9fec88e951d5f719a2a276959169.png

And when shadows are activated:

076d3f9fb6bc448ccb6aa26818485357.png

Is this a bug or a design choice? Is there any fix or workarround?