ID 518852 - Applying a Clamp Filter has no effect if Upper Value = 1.0

Problem summary
Applying a Clamp Filter has no effect if Upper Value = 1.0
 
This bug affects both Clamp Filters applied via the Filters menu and Bake Points.
 
Customer reported version
Mari 4.8v3
 
Customer reported platform
CentOS 7
 
Steps to reproduce
 
1) Open any project
 
2) Switch on HDR mode and reduce the View Transform Gain to ~0.25
 
3) Create a Cloud node

4) Change the Cloud node's Color B value to 2.0

5) Bake the Cloud node to a 16-bit Paint node
 
6) View the Paint node and make it the Paint Target 
 
7) Apply a Clamp Filter (Filters > Clamp)
 
8) In the Apply Clamp dialog, set Apply To as Current Paint Target and Upper Value as 1.0
 
9) Enable the Preview, the Cloud should be clamped to one value and appear flat
 
10) Click Apply
 
Expected behaviour
The Filter should apply correctly, and match the preview.
 
Actual behaviour
The Clamp Filter has no effect when Upper Value = 1.0:
 

 
 
Workaround
As an alternative to the Clamp Filter, a Clamp Adjustment layer or node can be used for clamping Upper Values to 1.0. This can then be baked to a new Paint node/converted to a Paintable Layer. 
 
Reproduced by support
This bug has been reproduced in:
Mari 5.0v4 - Windows 10 - CentOS 7.9
Mari 4.8v1 - Windows 10
Mari 4.7v1 - Windows 10
Mari 4.5v1 - Windows 10
Mari 4.2v1 - Windows 10
Mari 3.4v1 - Windows 10
Mari 3.0v1 - Windows 10 - CentOS 7.9
 
Earliest version tested
Mari 3.0v1 - This issue appears to be in all tested versions of the product