ID 545749 - UV Rectangle Tool doesn't produce expected results

Problem summary
UV Rectangle Tool doesn't produce expected results.
 
Customer reported version
Modo 16.1v6
 
Customer reported platform
Windows 10
 
Steps to reproduce
1) Download the attached file, then open it in Modo.

2) Navigate to the UV Layout and select the visible mesh in the Items Viewport.
 
3) In the UV Viewport, select and change UV: (none) to UV: veh_...
 
4) Navigate to the UV toolbar, and then press the "Rectangle..." and observe the results.
 
Expected behavior
The Rectangle... tool should produce a straight UV shell.

 
Actual behavior
The Rectangle... tool doesn't produce a straight UV shell.

 
Workaround
Use Orient option by pushing Rectangle... with Ctrl modifier button.
 
Reproduced by Support in:
Modo 16.1v6 - Windows 11, macOs 11.7 Big Sur
Modo 16.1v1 - Windows 11, macOs 11.7 Big Sur - regression
 
Unable to reproduce bug in:
Modo 16.0v4 - Windows 11, macOs 11.7 Big Sur
 
Earliest version tested
Modo 16.0v4 - This issue doesn't appear in this version and has regressed.