Q7FN - Changing the source type on my PC doesn't change the colour profile when in 50hz

[neodraig]

I use my Q7FN as a PC monitor for my PC which I use to manage all my contents (videos, music, gaming, browsing, desktop apps...)

According to what I was doing with my PC, I would go in the "source" to edit it and choose "PC" if I was brownsing or using desktop apps, "Game Console" if I was gaming, and "Blu-ray Player" if I was watching videos. 

When changing the source, the screen would turn black for less a second to apply the new profile, with dramatic changes as a result (depending of the source type, more saturated colours, faster response time...).

I noticed this doesn't work anymore, whatever source type I choose the profile won't change (the screen doesn't turn black as it used to do to change the profile)  and will stay oversaturated for the desktop use.

I tried to reset the TV, change the HDMI port but this didn't work. The only thing that seems to work is to deactivate the HDMI UHD colours, but then I won't access the HDR content.

Note that I didn't change anything on my PC and didn't update windows nor my the driver of my RTX 2080 Ti, the only thing I did is to switch to 50hz instead of 60hz  (to get a more stable framerate while playing games in 4K).