ID 458790 - Smoothing Groups are not saved on OSX when exporting as an FBX file.

Problem summary
Smoothing Groups are not saved on OSX when exporting as an FBX file.

Customer reported version
modo.14.1v2

Customer reported platform
10.15

Steps to reproduce

1) Create a simple cube
2) Open the "Smoothing Group UI" found in Geometry > Polygon.
3) Select 2 polygons on the cube and add them to group A.

4) Select a different 2 polygons on the cube and add them to group B.

5) Go to Preferences > File I/O > FBX I/O and enable "Save Smoothing Groups"

6) Export this as an FBX.

7) Open the FBX in a fresh scene file and notice that the saved Smoothing Groups aren't present.

Expected behaviour

The smoothing groups should be saved.

Actual behaviour

The smoothing groups are not saved.

Workaround
Unknown.

Reproduced by support

This bug has been reproduced in:
14.1v2 - OSX 10.15

14.1v1 - OSX 10.15

14.0v2 - OSX 10.15

14.0v1 - OSX 10.15

13.2v1 - OSX 10.15

13.1v1 - OSX 10.15

13.0v1 - OSX 10.15

12.2v2 - OSX 10.15

12.1v2 - OSX 10.15

Unable to reproduce bug in:
14.1v2 - Windows 10

Earliest version tested

12.1v2 - This issue appears to be in all versions of the product.