Comment 7 for bug 171795

This is happening with any way of using another SVG document from the main SVG document.

For example, consider this example:
https://rawgit.com/tanty/design-hodgepodge/master/svg/filter/igalia-feblend-feimage-explicit.svg

On it, we define another embedded SVG document in the "defs" part of the main document to use as graphic source for a filter.

Opening with Inkscape we can see how the embedded SVG has been rasterized :(