ID 370320 - Project Opens Without the Current Object Populating Palettes

Problem summary
Occasionally on project open, projects will not have an active nodegraph/channels/shader even though the object is selected in the Objects Palette and the shader displays visually correct in the canvas.

Customer reported version

Customer reported platform

Steps to reproduce

1. Occurs sporadically on project open after previously closing the project and discarding the save
OR
1. Open any project with an MCL
2. Add a few layers 
3. Projects tab > Double click same project
4. Select 'Discard' when prompted to save
5. When the Convert Layers dialog pops up - select 'Cancel'
6. Project opens not populated

Expected behaviour

Project should open with active object's nodegraph and channels available

Actual behaviour
No Channels can be created or are viewable, NodeGraph is locked and you are unable to switch to User Shader

Workaround
Creating a locator and switching back to the previous object reloads the nodegraph.

Reproduced by support
This bug has been reproduced in:

Mari 4.5v1 - Windows 10 - CentOS7 - regression

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

Earliest version tested
4.2v2 - This issue no longer appears in this version and has regressed