The failure mode is that "CONSOLE MESSAGE: Error: Not allowed to use indirect reference in <clip-path>" is missing from the output. That message comes from SVGUseElement::toClipPath. Not sure if anything about the way we handle SVG clip paths affects whether the console message is reported or not. Might be a timing thing where we need to wait longer for the message?
<rdar://problem/90164274>
*** This bug has been marked as a duplicate of bug 238066 ***