ID 360746 - Attaching a custom node to the Displacement Channel of a Shader Network causes a render error

Problem summary
Attaching the custom node to the Displacement Channel of a Shader Network causes a Shader error

Customer reported version

3.4v1/4.1v2

Customer reported platform

Multiple

Steps to reproduce

1) Launch Mari

2) Open Example Head

3) Register the attached custom node and create within your channel network

4) Attach your channel to the displacement slot of any Shader network (VRay, AiStandard, BRDF etc)

5) You'll receive a Shader Error, as below:

Workaround
Unknown. 

Reproduced by support
Mari 4.1v2 - Windows 7, CentOS 7
Mari 4.0v4
Mari 4.0v1
Mari 3.4v2 - Windows 7, CentOS 7

Earliest version tested

Mari 3.3v1 - Last working version

Expected behaviour
There should be no shader error in the viewport

Actual behaviour
An Unable to User Shader rendering error is displayed