I get the same issue with Affinity designer 2.0 and Affinity Studio
When looking in clipboard at the svg of a rectangle copied from Affinity, then pasted in VS and copied to clipboard from VS, I can see a difference :
Copied from Affinity : 992x525:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="992px" height="595px" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" xmlns:serif="http://www.serif.com/" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linejoin:round;stroke-miterlimit:2;">
<g transform="matrix(1,0,0,1,-384,-378)">
<g transform="matrix(1,0,0,1,-1176,-147)">
<rect x="1560" y="525" width="992" height="595" style="fill:rgb(235,235,235);"/>
</g>
</g>
</svg>
Copied from VS : 238x143
<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="239" height="143" viewBox="0 0 239 143" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" xml:name="Untitled-1">
<defs/>
<g transform="matrix(1.0 0.0 -0.0 -1.0 0.0 142.8) ">
<path d="M396.1966 18.5092 L396.1966 161.3092 634.2766 161.3092 634.2766 18.5092 396.1966 18.5092 Z" transform="matrix(1.0 0.0 0.0 1.0 -396.19663361 -18.50924665) " fill="#EBEBEB" fill-rule="evenodd"/>
</g>
</svg>