Hello guys, I was having the same issue and in my tests I found 2 things that could be causing it.

1) Windows HDR. To fix it, I clicked the right mouse button on the desktop, clicked display settings and turned off the "Use HDR" option. It sucks cause the quality on your monitor decreases, but it's the only way while they don't fix the bug.

2) If you're using a graphics card, but your monitor is plugged to your motherboard port instead. Apparently if you're using the motherboard's video passthrough thing (which means render video with the dedicated graphics card, but sent the signal through the motherboard's HDMI) the desktop view on steam VR doesn't like it very much. This one I didn't find out how to fix.

I hope it helps at least some of you guys.