ID 458925 - Expression linking two OCIOColorSpace nodes throws an error, after closing the script

Problem summary
Expression linking two OCIOColorSpace nodes throws an error, after closing the script. The following is an example of the error:

ERROR: oCIOColorSpace.in_colorspace: Nothing is named "OCIOColorSpace1".

Customer reported version
Nuke 12.2v3

Customer reported platform
CentOS 7

Steps to reproduce

1) Open Nuke.

2) Create two seperate OCIOColorSpace nodes in the Node Graph.

3) Expression link a knob from one OCIOColorSpace node, to the corresponding knob of the other OCIOColorSpace node. You can do this by running the following Python code in the Script Editor:

nuke.toNode('OCIOColorSpace2')['in_colorspace'].setExpression('OCIOColorSpace1.in_colorspace')

4) Close the script (File > Clear). 

5) Open the Terminal/Command Prompt window and notice that an error has been thrown, like so:

ERROR: oCIOColorSpace.in_colorspace: Nothing is named "OCIOColorSpace1"

Expected behaviour
Nuke should not throw an error once the script is closed.

Actual behaviour
Expression linking two OCIOColorSpace nodes throws an error, after closing the script.

Workaround
Unknown.

Reproduced by support

This bug has been reproduced in:
Nuke 12.2v3 - Windows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra)

Nuke 12.0v1 - Windows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra) - Regression

Unable to reproduce bug in:
Nuke 11.3v6 - Windows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra)

Earliest version tested
Nuke 11.3v6
- This issue doesn't appear in this version and has regressed