Steam causing a "Dead pixel"

[United_Stealth]

Whenever I start Steam, in the middle of the screen a black spot the size of 1 pixel appears. 

Sometimes it's only on the desktop, other times it's in every app there is, so basically always. 

I thought it was my monitor, gpu or cable. 

But I've tried different cables, gpu's, monitors, reinstalled drivers after safe boot > DDU. It always gives the same issue. That damn pixel in the middle of my screen. 

I also reinstalled my pc, everything was fine until I installed and started steam, BAM, it was back. So frustrating.....

Good news is that when I close it, it's gone. But it's weird that after even a fresh install it's there again. 

 

Whenever I take a screenshot of the pixel area, it also shows up in the screenshot. 

What on EARTH might be causing this?????????????????

 

It's on a new system with a:

3800x

3200mhz 16gb corsair vengance

msi b450m mortar, latest bios

samsung evo plus 500gb

 

Not new, from my old system which worked fine, now in my new one:

2x sandisk ultra ii ssd 960gb

vega 64 lc

 

Edit: SOLVED, by changing to Steam Beta version.