<p dir="auto"><strong>Do you want to request a <em>feature</em> or report a <em>bug</em>?</strong></p>
<p dir="auto">Report a bug.</p>
<p dir="auto"><strong>What is the current behavior?</strong></p>
<p dir="auto">Getting the following error while trying to hydrate SSR content.<br>
<code class="notranslate">Expected server HTML to contain a matching &lt;linearGradient&gt; in &lt;defs&gt;.</code></p>
<p dir="auto"><strong>If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via <a href="https://jsfiddle.net" rel="nofollow">https://jsfiddle.net</a> or similar (template for React 16: <a href="https://jsfiddle.net/Luktwrdm/" rel="nofollow">https://jsfiddle.net/Luktwrdm/</a>, template for React 15: <a href="https://jsfiddle.net/hmbg7e9w/" rel="nofollow">https://jsfiddle.net/hmbg7e9w/</a>).</strong></p>
<p dir="auto">The following check returns false<br>
</p><div class="Box Box--condensed my-2">
  <div class="Box-header f6">
    <p class="mb-0 text-bold">
      <a href="https://github.com/facebook/react/blob/177cd8525348c83a89962c426fa482b5c8ca4f39/packages/react-dom/src/client/ReactDOM.js#L453-L462">react/packages/react-dom/src/client/ReactDOM.js</a>
    </p>
    <p class="mb-0 color-fg-muted">
        Lines 453 to 462
      in
      <a data-pjax="true" class="commit-tease-sha" href="/facebook/react/commit/177cd8525348c83a89962c426fa482b5c8ca4f39">177cd85</a>
    </p>
  </div>
  <div itemprop="text" class="Box-body p-0 blob-wrapper blob-wrapper-embedded data">
    <table class="highlight tab-size mb-0 js-file-line-container" data-tab-size="8" data-paste-markdown-skip="">

        <tbody><tr class="border-0">
          <td id="L453" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="453"></td>
          <td id="LC453" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line"> <span class="pl-c1">canHydrateInstance</span><span class="pl-kos">(</span> </td>
        </tr>

        <tr class="border-0">
          <td id="L454" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="454"></td>
          <td id="LC454" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line">   <span class="pl-s1">instance</span>: <span class="pl-v">Instance</span> <span class="pl-c1">|</span> <span class="pl-v">TextInstance</span><span class="pl-kos">,</span> </td>
        </tr>

        <tr class="border-0">
          <td id="L455" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="455"></td>
          <td id="LC455" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line">   <span class="pl-c1">type</span>: <span class="pl-s1">string</span><span class="pl-kos">,</span> </td>
        </tr>

        <tr class="border-0">
          <td id="L456" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="456"></td>
          <td id="LC456" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line">   <span class="pl-c1">props</span>: <span class="pl-v">Props</span><span class="pl-kos">,</span> </td>
        </tr>

        <tr class="border-0">
          <td id="L457" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="457"></td>
          <td id="LC457" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line"> <span class="pl-kos">)</span>: <span class="pl-c1">boolean</span> <span class="pl-kos">{</span> </td>
        </tr>

        <tr class="border-0">
          <td id="L458" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="458"></td>
          <td id="LC458" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line">   <span class="pl-k">return</span> <span class="pl-kos">(</span> </td>
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        <tr class="border-0">
          <td id="L459" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="459"></td>
          <td id="LC459" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line">     <span class="pl-s1">instance</span><span class="pl-kos">.</span><span class="pl-s1">nodeType</span> <span class="pl-c1">===</span> <span class="pl-c1">ELEMENT_NODE</span> <span class="pl-c1">&amp;&amp;</span> </td>
        </tr>

        <tr class="border-0">
          <td id="L460" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="460"></td>
          <td id="LC460" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line">     <span class="pl-s1">type</span><span class="pl-kos">.</span><span class="pl-s1">toLowerCase</span><span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-c1">===</span> <span class="pl-c1">instance</span><span class="pl-kos">.</span><span class="pl-c1">nodeName</span><span class="pl-kos">.</span><span class="pl-c1">toLowerCase</span><span class="pl-kos">(</span><span class="pl-kos">)</span> </td>
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        <tr class="border-0">
          <td id="L461" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="461"></td>
          <td id="LC461" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line">   <span class="pl-kos">)</span><span class="pl-kos">;</span> </td>
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        <tr class="border-0">
          <td id="L462" class="blob-num border-0 px-3 py-0 color-bg-default" data-line-number="462"></td>
          <td id="LC462" class="blob-code border-0 px-3 py-0 color-bg-default blob-code-inner js-file-line"> <span class="pl-kos">}</span><span class="pl-kos">,</span> </td>
        </tr>
    </tbody></table>
  </div>
</div>
<p></p>
<p dir="auto">as <code class="notranslate">type</code> is <code class="notranslate">linearGradient</code> and <code class="notranslate">instance.nodeName.toLowerCase()</code> is <code class="notranslate">lineargradient</code></p>
<p dir="auto"><strong>What is the expected behavior?</strong></p>
<p dir="auto">Node types are compared correctly as SVG uses camelCase for tagName</p>
<p dir="auto"><strong>Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?</strong></p>
<p dir="auto">React 16</p>
<p dir="auto"><strong>Do you want to request a <em>feature</em> or report a <em>bug</em>?</strong><br>
Bug</p>
<p dir="auto"><strong>What is the current behavior?</strong><br>
I've started recieving this warning about my SVGs which is using <a href="https://developer.mozilla.org/en-US/docs/Web/SVG/Element/feGaussianBlur" rel="nofollow">feGaussianBlur</a>:<br>
<code class="notranslate">Warning: Expected server HTML to contain a matching &lt;feGaussianBlur&gt; in &lt;filter&gt;.</code></p>
<p dir="auto"><strong>What is the expected behavior?</strong><br>
Should be no warnings because there are no difference.</p>
<p dir="auto"><strong>Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?</strong><br>
Such behavior started right after updating to <code class="notranslate">React 16.0.0-rc.3</code> and never happened with <code class="notranslate">React 15.6.1</code></p>