ID 464206 - Using a high poly mesh with a displacement map and an Area Light causes extremely slow rendering.

Problem summary
Using a high poly mesh with a displacement map and an Area Light causes extremely slow rendering.

Customer reported version
modo.14.2v2

Customer reported platform
windows10

Steps to reproduce

1) Download and open the attached scene file.
2) Render the scene file.
3) Go to the Shader Tree and disable the displacement effect

4) Re-render the scene file.

Expected behaviour

The displacement effect shouldn't dramatically increase render time when used with an Area Light.

Actual behaviour
The render time is dramatically increased.

Workaround
Unknown.

Reproduced by support

This bug has been reproduced in:

14.2v2 - Windows 10, macOS 10.14

14.2v1 - Windows 10, macOS 10.14

14.1v2 - Windows 10, macOS 10.14

14.1v1 - Windows 10, macOS 10.14

14.0v1 - Windows 10, macOS 10.14

13.2v1 - Windows 10, macOS 10.14

13.1v1 - Windows 10, macOS 10.14

13.0v1 - Windows 10, macOS 10.14

12.2v2 - Windows 10, macOS 10.14

Earliest version tested

12.2v2 - This issue appears to be in all versions of the product.