ID 158140 - MergeExpression/Expression node errors on command line render when exr channel information is referenced in expression (Nothing named '...')

A Nuke script that contains an expression node which references a custom channel in an EXR file (e.g. channels rgba  = __globalMatte.red) will render fine in the GUI, but when rendering from the command line, the output isn't correct and an error appears:

 

ERROR: Expression.expr0: Nothing is named ''__globalMatte.red'

 

Customer reported version
Nuke 9.0v8

 

Customer reported platform
Linux

 

 

1) Read in an EXR file that contains custom channels (see attached example script).

2) Add an Expression node with an expression that references one of the custom channels.

 

3) Add a Write node and render the first frame - no errors appear.

 

4) Save the script and render the first frame from the command line -  the expression gives an error and the render will be incorrect.

 

ERROR: Expression.expr0: Nothing is named ''__globalMatte.red'

 

Reproduced by support
Reproduced in Nuke 9.0v8, 10.0v3 on Windows 7

Nuke7.0v1 - 9.0v5 MacOS & Windows

 

Expected behaviour
The script should render correctly in terminal mode just like in the GUI.

 

An error appears and the renders are incorrect.