The sad thing is ... where are the moderators to help us? bridge the gap between us and samsung, which is part of their job. Shameful all this. If they do not fix this problem I will sue samsung and all this neglect.
I bought Q90T yesterday after my KS8000 die and have not tried yet game mode. But there is dimming in TV mode or when watching video using apps like Youtube.
When most part of screen becomes black (for example on text or logo on black screen, credits, etc.) all other colors become dimmed.
All possible settings are switched off, firmware updated to 1403 via Internet, factory reset after update was performed.