ID 469005 - Mesh Fusion creates non-manifold edges when exported as a .STL

Problem summary
Mesh Fusion creates non-manifold edges when exported as a .STL

Customer reported version
modo.14.2v2

Customer reported platform
11_big_sur

Steps to reproduce

1) Download and open the attached scene file.
2) Right-click the Fusion Item Mesh and select Export Selected Layers.
3) Set the format to STL and select OK.

4) Open a new scene and import the STL file.

5) Notice that there are non-manifold edges in numerous places around the item.

Expected behaviour
There shouldn't be any non-manifold edges.

Actual behaviour
There are non-manifold edges in numerous places around the item.

Workaround
Unknown.

Reproduced by support

This bug has been reproduced in:

14.2v2 - Windows 10

14.2v1 - Windows 10

14.1v1 - Windows 10

14.0v1 - Windows 10

13.0v1 - Windows 10

12.2v2 - Windows 10

Earliest version tested
12.2v2 - This issue appears to be in all versions of the product.