ID 536540 - UVs have broken edge loops when using the Add Loop Tool

Problem summary
UVs have broken edge loops when using the Add Loop Tool.
 
Customer reported version
Modo 16.1v1
 
Customer reported platform
Windows
 
Steps to reproduce
1) Open Modo and navigate to the Model Toolbar.
2) In the 3D Viewport, create a cube mesh item by holding Shift and clicking the Cube Primitive button.
3) Navigate to the UV Layout, select the cube in the Items Viewport, then on the Model toolbar select the Edge tab, and in Tools select "Add Loop".
4) Press the left mouse button on the mesh and drag the edge loops inward while observing the UV. 
 
Expected behavior
The UV map should have added edge loops that remain connected.

 
Actual behavior
When adding new edge loops, the edge loops appear broken on the UV map.

 
Workaround
To prevent the Edge Loop Tool from experiencing this unexpected behavior, enable the option "Keep Quads" and test if the behavior continues to occur. If the behavior persists, also enable the "Preserve Curvature" option and set the Tension to 0.

 
Reproduced by Support in:
Modo 16.1v1 - Windows 11, macOS 10.15 Catalina -regression
 
Unable to reproduce bug in:
Modo 16.0v4 - Windows 11, macOS 10.15 Catalina
 
Earliest version tested
Modo 16.0v4 - This issue doesn't appear in this version and has regressed.