ID 511571 - Parameter expression within NME are not preserved when saving

Problem summary
Parameter expressions on shading nodes within an NME are not preserved when saving a scene, only writing out the resolved value. This results in the expression being lost when next loading the scene. 
 
Customer reported version
Katana 4.0v7
 
Customer reported platform
 
Steps to reproduce
 
1) Create an NME node and enter it

2) Create a shading node

3) Add a user parameter to that shading node
 
4) Make any parameter's expression point to the user parameter
 
5) Save the scene
 
Expected behaviour
The parameter expression is written out in the .katana scene file
 
Actual behaviour
Only the resolved value of the expression is written out
 
Workaround
Unknown
 
Reproduced by support
 
This bug has been reproduced in:
Katana 4.5v3 - Windows 10
Katana 4.0v8 - Windows 10
Katana 4.0v7 - Windows 10
Katana 3.6v5 - Windows 10
Katana 3.6v1 - Windows 10
Katana 3.5v5 - Windows 10
Katana 3.5v1 - Windows 10
 
Earliest version tested
Katana 3.5v1 - This feature did not exist before this version