ID 234056 - 3.1v2 and 3.1v3 launches with incorrect GPU settings

Problem summary
Some tools such as blur and clone stamp tool work in the linear colour space regardless of channel depth. As a result, blurring or cloning an image in an 8-bit sRGB channel results in mis-matched results. 

Customer reported version

3.1v3

Customer reported platform
10.11

Steps to reproduce

1) Launch Mari 3.1v2/3 on Mac OS 10.11

2) Load the default head project (Go to Help>Create Default Project)

3) Select the blur tool (Tear drop icon) and smear some of the skin

4) What appears in the paint buffer is incredibly brighter than the expected outcome

Workaround
Modifying the GPU settings seems to fix this. 

If you disable 'Variance maths' then this behaviour is rectified

Reproduced by support
Reproduced by Support on 

Mac Pro 10.11.6 El Capitan
AMD D700

iMac 10.11.6 El Capitan

ATI Radeon HD 5750

Expected behaviour
See comparison below