Unexplainable recurrent & overly excessive skin lighting contrast

[Dodik]

For the first time I experienced an excessive contrast all over the processed face immediately after the program rendered the image, applying its own skin lighting algorithms, making the face all-gray.
To find out what caused that I disabled skin lighting controls option and the skin returned to its pre-processed color.
When I attempted to use a touch-up brush to fix some under-eye skin issues, the skin lighting control automatically got engaged with the face, once again, turning gray.
What's up with that and what's causing it?

My version is # v.11.2.9.

[gdamaggio]

Few months ago I opened a discussion on the same topic. Unfortunately the only solution I found was to disable skin colouring controls.
I understand that even Portrait Professional staff could not help us