ID 482700 - More noise is produced with metallic materials with high roughness

​Problem summary
More noise is produced with metallic materials with high roundness.
Customer reported version
modo.15.0v3
Customer reported platform
windows10
Steps to reproduce
1) Download the attached scene file.
2) Open the scene file inside of Modo.
3) Press F9 to render the scene file, and save the image. 
Expected behaviour
The same amount of noise should be produced.
Actual behaviour
More noise is produced.
Workaround
Unknown.
Reproduced by support
This bug has been reproduced in:
15.0v3 - Windows 10
15.0v1 - Windows 10 -regression
Unable to reproduce bug in:
14.2v2 - Windows 10

Earliest version tested
14.2v2  - This issue doesn't appear in this version and has regressed