Vray region render issue

Hi
I am working with V-ray 5 + Sketchup Pro 2020.
I render with Irridiance Map, Light Cache.
When I render a scene everything OK.
Then I try to render a little area in the VFB image with Region Render,
and unfortunately I get a slightly different tone of the color.
It is minor, but it is different.
What is the reason for this ?
How can I fix it?
I attach a before and after examples, and the settings file.
Thanks
Rachel

after
before