Comment 1 for bug 1075325

> what the SVG spec says about how to interpret such cases.

«(…) In general, this means that the presentation attributes have lower priority than other CSS style rules specified in author style sheets or ‘style’ attributes.

User agents that do not support CSS must ignore any CSS style rules defined in CSS style sheets and ‘style’ attributes. In this case, the CSS cascade does not apply. (Inheritance of properties, however, does apply. See Property inheritance.)»
<http://www.w3.org/TR/SVG11/styling.html#UsingPresentationAttributes>

Did you also file a report for the 'QtSvg' module? (Note that librsvg seems to fail with such gradients too, whereas other SVG implementations like modern browsers, and Squiggle (Batik 1.7, 1.8pre) use the color from the CSS style attribute as expected, and ignore the presentation attribute if the 'style' attribute is present.