ID 364176 - Using a Rectangle node after a Keyer and Remove node causes endless rendering

Problem summary
Using a Rectangle node after a Keyer node and Remove node (keeping rgb) doesn't render.

Customer reported version
nuke.11.1v4

Customer reported platform
centos6

Steps to reproduce

1) Create a keyer node.
2) Create a remove node and change to 'keep' and channel to 'rgb'.
3) Create rectangle node.
4) Click the rectangle node and hit 1 on the keyboard to View it.
5) The Viewer render icon in the top right of the screen turns red, indicating the viewer is rendering but never finishes. 
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Workaround
Unknown.

Reproduced by support
This bug has been reproduced in:
11.2v3 - OSX 10.12.6 - Windows 10 - CentOS7
11.2v1 - OSX 10.12.6
11.1v6 - OSX 10.12.6
11.1v1 - OSX 10.12.6
11.0v4 - OSX 10.12.6
11.0v1 - OSX 10.12.6
10.5v7 - OSX 10.12.6
10.5v1 - OSX 10.12.6
10.0v6 - OSX 10.12.6
10.0v1 - OSX 10.12.6
9.0v9 - OSX 10.12.6
9.0v1 - OSX 10.12.6
8.0v7 - OSX 10.12.6
8.0v1 - OSX 10.12.6
7.0v10 - OSX 10.12.6 - Windows 10 - CentOS7

Earliest version tested
7.0v10 - This issue appears to be in all versions of the product
Expected behaviour
Viewer should eventually complete rendering.

Actual behaviour
Rectangle node causes Viewer to render endlessly.