Does Xamarin ffimageloadingsvg:SvgCachedImage have different rules from the web when it comes to interpreting CSS in svgs?

Question

Here is an example:

This svgs works in Google, Illustrator but not XF when using ffimageloadingsvg:SvgCachedImage

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
    <defs>
        <style type="text/css">
            .cls-1 {
                fill: none;
            }
            .cls-2 {
                fill: none;
                stroke: #666;
                stroke-miterlimit: 10;
                stroke-width: 9px;
            }
        </style>
    </defs>
    <rect class="cls-1" width="512" height="512" />
    <circle class="cls-2" cx="256" cy="256" r="251.5" />
</svg>

This svgs works in Google, Illustrator and XF when using ffimageloadingsvg:SvgCachedImage

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
    <defs>
        <style type="text/css">
            .cls-1, .cls-2 {
                fill: none;
            }
            .cls-2 {
                stroke: #666;
                stroke-miterlimit: 10;
                stroke-width: 9px;
            }
        </style>
    </defs>
    <rect class="cls-1" width="512" height="512" />
    <circle class="cls-2" cx="256" cy="256" r="251.5" />
</svg>