Further tests show that the underlying cause seems to be that in cairo-based exports transparent bits of the mask are differently interpreted than by Inkscape:
In Inkscape, regions with minimum Alpha (zero alpha) are fully transparent.
In cairo-based exports, regions with minimum Alpha (zero alpha) are fully opaque.
Further tests show that the underlying cause seems to be that in cairo-based exports transparent bits of the mask are differently interpreted than by Inkscape:
In Inkscape, regions with minimum Alpha (zero alpha) are fully transparent.
In cairo-based exports, regions with minimum Alpha (zero alpha) are fully opaque.