ID 399191 - Viewport Ambient Occlusion is not working correctly on some AMD cards.

Problem summary

This issue has occurred when using both the Radeon Pro WX7100 and Radeon VII GPUs.

Customer reported version
modo.13.0v1

Customer reported platform
windows10

Steps to reproduce

1) Open Modo and create a simple cube primitive.

2) Create a plane underneath the cube item.

4) Press the O key to open the 3D Viewport Properties, and go to the Inactive Meshes tab, enable Make Inactive Same as Active.

5) Go to the Advanced Options tab and select Enable Ambient Occlusion.

6) Notice how it doesn't appear in the 3D Viewport, and if you adjust the Radius value it doesn't work as intended.

Expected behaviour
The ambient occlusion of the items should show within the 3D viewport. 

Actual behaviour

Nothing appears within the 3D viewport and if you increase the Radius value it doesn't work as intended.

Workaround
If you enable HMD Ultra Quality the 3D viewport ambient occlusion is shown.

Reproduced by support

This bug has been reproduced in:

Modo 13.0v1 - Windows 10

Modo 12.2v2 - Windows 10

Modo 12.1v2 - Windows 10

Modo 12.0v1 - Windows 10

Modo 11.2v3 - Windows 10

Modo 11.1v1 - Windows 10

Modo 11.0v3 - Windows 10

Modo 10.2v4 - Windows 10

Earliest version tested

Modo 10.2v4 - This issue appears to be in all versions of the product.