ID 393336 - Volumetric light rendering issues.

Problem summary

When rendering with volumetric lights black squares appear in the final render.

Note: This only affects Windows version of Modo, both Linux and OSX don't encounter this issue. 

Customer reported version
modo.13.0v1

Customer reported platform
windows10

Steps to reproduce

1) Create a cube mesh and press D to subdivide this mesh.

2) Select and delete a single polygon on this mesh.

3) Navigate to the Items list and select Add Item>Items/Lights>Spot Light.

4) Move this light so it's inside of the created cube mesh and face it through the hole.

5) Zoom out and then render the view, notice the small squares around the sides of the render.

Expected behaviour
These squares shouldn't appear when rendering volumetric lights.

Actual behaviour
Squares appear when rendering volumetric lights.

Workaround
Unknown.

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 -regression

Unable to reproduce bug in:

Modo 11.2v3 - Windows 10

Earliest version tested
Guidance: List earliest version you've tested and the reason you stopped there. Reasons can be: 

Modo 11.2v3 - This issue no longer appears in this version and has regressed.