ID 366514 - Mari's quick project tool projects darker than expected

Problem summary
Mari's quick project tool projects darker than expected

Customer reported version
v4 and higher

Customer reported platform
windows10

Steps to reproduce

1) Open Mari 

2) Open the attached archive

3) Go to Camera -> Quick Projection Settings and specify the path for a new image and 8-bit depth

4) Press 5 for centering the front view

5) Go to Camera -> Quick Unproject

6) Change the unprojected image using another program 

7) Select an area of the model using the Marquee Select Tool 

8) Go to Camera -> Quick Project Front

Workaround
In the Quick Projection Settings choose 16-bit instead of 8-bit 

Reproduced by support
Reproduced. It does not happen with other Mari archives. 

This bug has been reproduced in:
Mari 4.2v1 - CentOS 6.9 - Windows 10 
Mari 4.1v2 - CentOS 6.9 - Windows 10 
Mari 3.4v3 - CentOS 6.9 - Windows 10

Unable to reproduce bug in:
Mari 4.0v4 -  CentOS 6.9 - Windows 10 

Earliest version tested
Mari 4.0v4 - This issue no longer appears in this version and has regressed

Expected behaviour
Quick Project Tool to projects the normal color values of the image

Actual behaviour
Quick Project Tool projects darker color values.