ID 379328 - Moving or exporting rigging elements such as joints, IK and parent constrains to a new scene fails on import

Problem summary
Moving or exporting rigging elements such as joints, IK and parent constrains to a new scene fails on import. 

Customer reported version
Modo 12.1v2 

Customer reported platform
Windows 10 

Steps to reproduce

Alternative 1 

1) Open the attached scene. The scene contains group folders with mesh parts, joints and rigging elements such as IK and parent constraints. 

2) Select the entire hierarchy of the folder named "Rigging_Elements_GRP" that contains the rigging elements. 

3) Create a new scene and drag the selected folder into it. There is now an error message appearing explaining that the imported folder could not be imported into the new scene. 

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Alternative 2 

1) Open the attached scene. 

2) Select the entire hierarchy of the folder named "Rigging_Elements_GRP". 

3) Right-click the folder and then select the "Export Selected" option. Export the selected folder to a new "MODO scene" file. 

4) The same error message is now appearing and exporting the selected folder to a new scene file has failed. 

Workaround
Unknown.

Reproduced by support

This bug has been reproduced in:
Modo 12.2v1 - Windows 10 - CentOS 7 - MacOSX 10.13 
Modo 12.1v2 - Windows 10 
Modo 12.0v1 - Windows 10 
Modo 11.2v3 - Windows 10 
Modo 11.1v1 - Windows 10 
Modo 11.0v3 - Windows 10
Modo 10.2v4 - Windows 10 - CentOS 7 - MacOSX 10.13 

Notes: In Modo 11.1v1 and versions below, the character rig can be exported to a new scene but is broken on import. 

Earliest version tested
Modo 10.2v4 - This issue appears to be in all versions of the product.

Expected behaviour
Moving or exporting any rigging elements such as joints, IK and parent constrains to a new scene should be proceeded without issues.

Actual behaviour
When moving or exporting rigging elements to a new scene it fails on import.