NodeGroup not working in materials (4.00 v16.3)

[ChrisH]

I'm having a problem with NodeGroups in materials not working. I made new file to test it (attached), to make sure the problem wasn't with the file I was working on.

If I'm in Rendered View/Interactive Mode and create a group of some nodes in a material, the viewport won't update and the status stays at "Waiting for image...".
It doesn't update if I make changes to the shader etc in the group (not until I ungroup the node group). If I zoom, pan etc the Viewport will update, but with the material as it was before creating the node group.
If I then update the scene (or stop/start the rendered view), or do render the image, that node group will appear as an white diffuse (standard/unassigned material), even if I use mix nodes etc.

I've looked at the logs and can't see any messages that differ from before I create the node group to after.

Screencast showing the problem: https://drive.google.com/file/d/1w6AqgP ... sp=sharing

A. Windows 10
B. GTX 1080 - 8GB
C. 16GB
D. 398.11
E. 3.08
F. 4.00 v16.3
G. Blender 2.79b

[J.C]

It looks like the Node Graph Upload Optimization needs to be fixed so Node Groups can work.
For now just turn off "Node Graph Upload Optimization" in the Octane options if you need Node Groups in your scene.

[ChrisH]

Thank you, turning off "Node Graph Upload Optimization" worked!