ID 380027 - Mesh lines appear in the Scanline Render image while anti-aliasing and multiple samples are available

Problem summary:
Mesh lines appear in the Scanline Render image when using an Expression node while anti-aliasing and multiple samples are available.

Customer reported version:
nuke.11.1v6

Customer reported platform:
fedora

Steps to reproduce:
1) In Nuke, create a Constant node.

2) Create and attach a Card or other Geometry item.

3) Create and link a Scanline Render node with a Camera.

4) Create and attach an Expression node to the Scanline Render.

5) Add an expression in the channel RGBA as: (a-1)*1000000

6) Attach the Viewer to the Expression node and observe the Viewer.

Workaround:
Disable antialiasing in the Scanline Render node, or keep the MultiSample > samples value at 1.

Reproduced by Support in:
Nuke 11.3v1 - Windows 10, CentOS 7, macOS 10.13 High Sierra

Nuke 11.2v1 - Windows 10

Nuke 11.1v1 - Windows 10

Nuke 11.0v1 - Windows 10

Nuke 10.5v1 - Windows 10

Nuke 10.0v1 - Windows 10

Nuke 9.0v1 - Windows 10

Nuke 8.0v1 - Windows 10, CentOS 7, macOS 10.13 High Sierra​

Earliest version tested:
Nuke 8.0v1 - This issue appears to be in all versions of the product

Expected behavior:
The Scanline Render image should appear free of wireframe/mesh lines.

Actual behavior:
Wireframe/Mesh lines appear on the image when viewing the Expression node with the alpha multiplied.