Why does HTML entities are still encoded in Code Block?

In the Code Block if I type in reversed character, they are encoded to HTML entities:

• Input:
  

• Output:

  <pre class="wp-block-code"><code>'[] </code></pre>
  

Meanwhile, if I put them in the custom HTML block, the output characters aren’t encode:

• Input:
  

• Output:

  <code>'[]</code>
  <code class="'[]"></code>
  <code><code class="'[]"></code></code>
  <pre class="wp-block-code"><code>'[]</code></pre>
  

I wonder why this should be the case? I enable troubleshooting mode and use the Twenty Twenty-One theme.

_{Related: Why does the custom HTML block not preserve the HTML characters?}