Occours in https://commons.wikimedia.org/wiki/File:Labanotation2.svg and in https://commons.wikimedia.org/wiki/File:Nixie_IN17.svg:

In https://commons.wikimedia.org/wiki/File:T194582_filter.svg the filter is not applied: (number 9 looks different than 0)
<path filter="url(#a)" transform="matrix(-.197 0 0 -.197 474.15 222.85)"/>

In https://commons.wikimedia.org/wiki/File:T194582_href.svg it doesn't blur the twice mirrowed path: (some path are not blured)
<use transform="matrix(-1 0 0 -1 0 0)" xlink:href="#a"/>

in https://en.wikipedia.org/w/index.php?title=Wikipedia:SVG_help&oldid=1142399289#Rendering_gradients is a problem reported about https://en.wikipedia.org/wiki/File:20210709_Bowling_-_strikes_versus_set_scores_-_scatter_plot.svg conataing a rotation applied to a linearGradient

<defs>
<linearGradient id="TrendChannel" x1="0" x2="0" y1="0" y2="1">
 <stop offset="0%" stop-color="white" />
 <stop offset="40%" stop-color="#dcdcff" />
 <stop offset="60%" stop-color="#dcdcff" />
 <stop offset="100%" stop-color="white" />
</linearGradient>
</defs>

<rect fill="url(#TrendChannel)" transform="translate(0,740) rotate(-47.5)"  width="2000" height="300"/>