When I copy an image directly from Paint.NET to Paint Tool SAI, the image appears slightly offset - the image is shifted three pixels to the left, with the leftmost three pixel columns appearing on the right side of the image, shifted down 1 pixel:
Example image copied from Paint.NET:
How it appears after being pasted into Paint Tool SAI:
Behavior seems to be consistent regardless of image size, in other words it's always three pixels off even if I downscale the image:
This doesn't occur if the same image is pasted from anywhere else I've tested (browser, discord, photoshop, etc) leading me to believe it's an issue with Paint.NET in particular and not with Paint Tool SAI.