tspan that changes the text direction is placed incorrectly

From https://svgwg.org/svg2-draft/text.html#DirectionProperty -

<?xml version="1.0" encoding="utf-8"?>
<svg xmlns="http://www.w3.org/2000/svg"
     width="100%" height="100%" viewBox="0 0 600 72"
     direction="rtl" xml:lang="he">

  <title direction="ltr" xml:lang="en">Right-to-left Text</title>
  <desc direction="ltr" xml:lang="en">
    An example for using the 'direction' and 'unicode-bidi' properties
    in documents that predominantly use right-to-left languages.
  </desc>

  <text x="300" y="50" text-anchor="middle" font-size="36"> כתובת MAC:&#x200F;
    <tspan direction="ltr" unicode-bidi="embed">00-24-AF-2A-55-FC</tspan> 
  </text>
</svg>

This is rendered incorrectly; the address inside the tspan overlaps the RTL text.