ID 576655 - OpenSpline width and feather and BSpline feather values cannot be queried with expressions or Python

Problem summary
OpenSpline width and feather and BSpline feather values cannot be queried with expressions or Python
 
Other roto shapes and point/curve values return correctly
 
Customer reported version
nuke.13.2v7
 
Customer reported platform
windows10
 
Steps to reproduce
 
1) Open Nuke

2) Create a Roto node and draw an OpenSpline

3) Right click a point on the open spline>curve editor...>all
In the Curve Editor, you can see the curves for feather, left(x/y), main(x/y), right(x/y) and width:
 

 
4) Select the width, right click>Edit>Copy>Copy Links
 
5) Make any other node, like a Transform node, and right click an animatable knob>Add expression...
 
6) Paste the link, removing the {} from the beginning and end of the expression, it will error saying nothing is name width:
 

 
This happens for width and feather for OpenSplines and feather(x/y) for BSplines
 
Expected behaviour
For the expression Nuke generated to access the values
 
Actual behaviour
The expression fails saying nothing is named that. Also there is no Python way to workaround this issue.
 
Workaround
None
 
Reproduced by support
This bug has been reproduced in:
Nuke 15.0v4 - Windows 10, Rocky 9.2, macOS Monterrey
Nuke 12.0v1 - Windows 10, macOS Monterrey
 
 
Earliest version tested
Nuke 12.0v1 - This issue appears to be in all tested versions of the product