[BUG] contrast level resets upon h264 video playback

Device: Tanix TX5Pro S905X(2GB) connected via hdmi to Samsung TV
Build: throughout 8.0.1-8.02

How to reproduce:
Play Sample1
Set contrast above or below 50 (e.g. 40) and set as default for all media
Play Sample2
Contast resets immediately, but the preset level witnin Video OSD Settings remains the same.

The problem is related to H264 HW acceleration, no bug if turned off. Also never resets on Jarvis builds.

Why needed to fix?

My LCD screen lost some brightness over time while contrast remains high(no way to change it within TV), so I lower it down in Kodi, but it gets up over and over again.

Sample1
Sample2

Quote from mmpp

Already fixed with the "nougat" development kernels. Use releases from here to try for yourself [TESTING][S905(X)] 10bit/HDR/Dithering Test Builds & Discussion or wait for these changes to make it into other releases

Just checked 8.0.2-testing3 build - no change there. Contrast stil resets with my samples.

I came across a simple workaround with modified path /sys/class/video/contrast

Adding this to autostart

#!/bin/sh
echo -40 > /sys/class/video/contrast
chmod 444 /sys/class/video/contrast

Could fix the problem, but no luck again as system resets all settings to defaults.