Steps to Reproduce:

1. Create an expand block
2. Inside the expansion block, create a code block, and set collapsible=true
3. Save the page
4. Click the expansion link to show the codeblock in it's collapsed state
5. Click the codeblock's expansion link

The storage format for the example is as follows:

<ac:structured-macro ac:name="expand">
  <ac:rich-text-body>
    <ac:structured-macro ac:name="code">
      <ac:parameter ac:name="linenumbers">true</ac:parameter>
      <ac:parameter ac:name="collapse">true</ac:parameter>
      <ac:plain-text-body>
        <![CDATA[#style { font-weight: bold; }]]>
      </ac:plain-text-body>
    </ac:structured-macro>
  </ac:rich-text-body>
</ac:structured-macro>

Expected Results

The code block should expand and be visible.

Actual Result

The code block expands, and disappears as the outer expand is (incorrectly) collapsed.

Workaround

Expand the outer expand macro again, to reveal the expanded codeblock.

Notes

The reverse is well - collapse the code block, and the outer expand will collapse as well.