This is a weird one to explain, when pasting to photoshop using an Alt+Print Screen screen capture, I am having the issue of photoshop taking a layer of pixels from the right side of the copy and putting it on the left of the canvas. This does not happen when pasting to other programs (I tried Paint and Pixlr on web)
This issue just started for me, I am running the latest version, 25.11, which I just reinstalled to try and fix the problem. I am running on Windows 10 Home, 64. Here is an image of the Flag of Seychelles to hopefully show what is happening. It's a little touch to see in this image upload, but your can see the red, white, and green to the left of the blue.
If you need any more information, just ask.