ID 415749 - When saving and reopening a scene Mari forgets set channel settings if the channel has been imported as a .mng.

Problem summary
When saving and reopening a scene Mari forgets set channel settings if the channel has been imported as a .mng.

Customer reported version
mari.4.6v1

Customer reported platform
windows10

Steps to reproduce

1) Open Mari and create a new blank project, make sure to deselect all channels when creating the project.
2) In the Node Graph create an Arnold Standard Surface (Shader Network) node.
3) Now add a Channel Node called 'Default', set the options shown below and select 'Ok'.

4) Attach the Channels node output to the Arnold Standard Surface nodes Diffuse Weight.

5) Select both of the nodes, right-click and select File>Export Nodes set the filetype to .mng and select 'Save'

6) Now delete these nodes from the scene and reimport them by right-clicking and selecting File>Import Nodes.

7) Select the .mng file that you exported.

8) Now go to the Channels palette and edit the 'Default' Channel to have the selections shown below:

9) Save the project and then close the project.

10) Reopen the project and notice that not all of the changes were saved.

Expected behaviour

Channel changes should be saved.

Actual behaviour
Some of the channel changes are forgotten.

Workaround
Unknown.

Reproduced by support

This bug has been reproduced in:
4.6v1 - Windows 10 - Centos 7 
4.5v2 - CentOS 7.5

Unable to reproduce bug in:
4.2v2- Windows 10 - Centos 7

Earliest version tested

4.2v2 - This issue doesn't appear in this version and has regressed.