ID 486215 - Rounded Edge Shader produces errors when rendered.

Problem summary
Rounded Edge Shader produces errors when rendered.

Customer reported version
modo.15.1v1

Customer reported platform
windows10

Steps to reproduce

1) Launch Modo.

2) Duplicate the cube in Polygon mode. 

3) Move it so it still intersects the previous cube.

4) Switch to Edge mode and select all edges.

5) Pick up the Edge Bevel tool and set Round level to 2.

6) Bevel the rounded edges as demonstrated in customer recording.

7) Apply material.

8) Go to Shader Tree and select the material.

9) Scroll down to Rounded Edge Width and Angle and set as follows:

10) Open Render Preview and when image is rendered note that intersection points are showing black lines.

11) Set to Weight by Polygon Area.

12) Observe that the issue disappears.

Expected behaviour
Intersection points should not show black lines

Actual behaviour
Black lines at intersections appear, unless Weight by Polygon Area is set.

Workaround
Set Weight by Polygon Area.

Reproduced by support

This bug has been reproduced in:
15.1v1 - Windows 10
15.0v1 - Windows 10
14.2v1 - Windows 10
14.1v1 - Windows 10
14.0v1 - Windows 10
13.0v1 - Windows 10
12.2v2 - Windows 10


Earliest version tested
- This issue appears to be in all versions of the product