ID 528324 - GafferThree 'solo' is not working when the light samples parameter is set to greater than 0

Problem summary
Katana ignores mute/solo lights for PRMan lights that have the parameter light sample set to a value greater than 0.
 
Customer reported version
Katana 5.0v3
 
Customer reported platform
CentOS7
 
Steps to reproduce
1) In a GafferThree node right click and add two of any prman light (for example the PxrDiskLight)

2) Select light 'A" and click on 'Mute/Solo' button.

3) Select light "B" and go to advance and change Light Samples to a value greater than 0.
 
4) Render.
 

 
Expected behaviour
I expected that light "A" would be the only one that renders as solo was selected.
 
Actual behaviour
Both lights appeared when rendering.
 
Workaround
Unknown.
 
Reproduced by support
This bug has been reproduced in:
Katana 5.0v3 - CentOS 7 - Windows 10
Katana 5.0v1 - CentOS 7
Katana 4.5v1 - CentOS 7
Katana 4.0v1 - CentOS 7
Katana 3.6v1 - CentOS 7
Katana 3.5v1 - CentOS 7
Katana 3.2v1 - CentOS 7
Katana 3.1v1 - CentOS 7
 
Unable to reproduce bug in:
Katana 3.0v1 - CentOS 7 - Windows 10
 
Earliest version tested
Katana 3.0v1 - CentOS 7 - Windows 10 - This issue doesn't appear in this version and has regressed