ID 574203 - Matcaps don't turn off in the Default 3D Viewport

Problem summary
Matcaps don't turn off in the Default 3D Viewport.
 
Customer reported version
modo.17.0v1
 
Customer reported platform
Windows 11
 
Steps to reproduce
 
1) Download the attached file and open it in Modo.

2) Navigate to the Shader Viewport and select the Matcap Shader layer.

3) In the selected layer's Texture Layers tab, toggle the Enable option off and on to observe the results.
 
Expected behavior
Toggling the Matcap Layer's Enable option off should disable it in the Default 3D Viewport.
 
Actual behavior
Toggling the Matcap Layer's Enable option off does not disable it in the Default 3D Viewport.
 
Workaround
Unknown.
 
Reproduced by Support in:
Modo 17.0v4 - Windows 11, macOS 11.7 Big Sur
Modo 17.0v1 - Windows 11, macOS 11.7 Big Sur - regression
 
Unable to reproduce bug in:
Modo 16.1v8 - Windows 11, macOS 11.7 Big Sur
 
Earliest version tested
Modo 16.1v8 - This issue doesn't appear in this version and has regressed.