Does not reproduce in 2019.1.11f1
Repro steps:
1. Use a project with HDRP
2. Create a PBR shadergraph
3. Create a material and assign your PBR shadergraph to your material
4. Create a sphere in the scene and assign your material to the sphere
5. Open your PBR shadergraph
6. Create a "gradient noise" node
7. Assign the output of the gradient noise node to the master node's alpha input (this should result in noise-shaped holes in your material)
8. Open the master node settings and enable "two sided"
9. Save
10. Go to the sphere in your scene

Expected result: you should be able to see the back facing geometry through the holes in your sphere
Actual result: you cannot see the back facing geometry because the two sided option doesn't do anything

Addendum: there is another shadergraph where two sided does not work in HDRP (as of the current master branch, 7.1.1 commit db2269d65f). These are:
Hair Graph (HDRP)