ID 519333 - Using an under operation the in the timeline Viewer with super white alphas (values above 1) and Obey Alpha enabled creates unexpected results

Problem summary
Using an under operation the in the timeline Viewer with super white alphas (values above 1) and Obey Alpha enabled creates unexpected results
 
This happens with images, or generated items on the timeline, like burn ins. This doesn't seem to affect over blend modes like over or minus
 
Customer reported version
nuke.13.2v3
 
Customer reported platform
 
Steps to reproduce
 
1) Download the attached highValuesCheckerBoard.exr and highValuesColorWheel.exr files

2) Open Nuke Studio and import the files

3) Add both clips to a sequence above each other
 
4) Select the top clip and press 1 to load it into the A Buffer
 
5) Select the bottom clip and press 2 to load it into the B Buffer, you should see incorrect results
 
6) Disable Obey Alpha in the Viewer, you should see the correct image
 
Expected behaviour
For the image to display correctly:

 
 
Actual behaviour
When the images have super whites, the areas turn black when using under
 

 
Workaround
Disable Obey Alpha
 
Reproduced by support
This bug has been reproduced in:
Nuke Studio 13.2v4 - Windows 10, CentOS 7.5, macOS 12
Nuke Studio 10.5v8 - Windows 10, CentOS 7.5 - regression
 
Unable to reproduce bug in:
Nuke Studio 10.0v1 - Windows 10, CentOS 7.5
 
Earliest version tested
Nuke Studio 10.0v1 - This issue doesn't appear in this version and has regressed between 10.5v8 and 10.0v1