Too Dark renders

[djnoone]

Regularly my renders came out darker than usual.
Sometimes when i change the resolution to a lower outcome the problem disappear.
Sometimes when i change from JPG to PSD the problem disappear.
Sometimes when i change some material.
But in 50 percent of renders, the outcome is muddy.
If i change a JPG out from the render window there is no problem. After the rendering is done and image styles have applied the problem occurs.
I use RTX 2070 for rendering (i cannot verify but on CPU the problem is either rare or non-existent)
Card driver is up to date.

There are no particular settings that can avoid or cause this.
It is valid for ver.9 and version 10.