Tabs rendered inside Colorbox are displayed with wrong labels

Disclaimer: I'm not sure weather this issue rather belongs to field_group, colorbox oder colorbox_node, sorry if I'm wrong here.

I'm using colorbox_node to open nodes listed by a view inside a colorbox overlay.
My content type's fields are grouped into horizontal tabs. Tabs are called "A", "B" and "C".

When viewing a node on its own the horizontal tabs work just as expected, they're simpy labeld "A", "B" and "C".

As soon as nodes are opened inside a colorbox those tab labels get either "Show" or "Hide" strings prepended, depending on weather the horizontal tab element is set to open or collapsed in the display settings. So the tabs look like "Hide A", "Hide B", "Hide C".

That string isn't wrapped inside any kind of markup so I can't find a way to hide this (but using a string function to search and replace, which I rather wouldn't wanna do).

Here's the (correctly) rendered output when viewing a node *not* inside a colorbox:

<ul class="horizontal-tabs-list">
  <li class="horizontal-tab-button horizontal-tab-button-0 first" tabindex="-1">
    <a href="#">
      <strong>A</strong>
      <span class="summary"></span>
    </a>
  </li>
  <li class="horizontal-tab-button horizontal-tab-button-1 selected" tabindex="-1">
    <a href="#">
      <strong>B</strong>
      <span class="summary"></span>
      <span id="active-horizontal-tab" class="element-invisible">(aktiver Reiter)</span>
    </a>
  </li>
  <li class="horizontal-tab-button horizontal-tab-button-2 last" tabindex="-1">
    <a href="#">
      <strong>C</strong>
      <span class="summary"></span>
    </a>
  </li>
</ul>

And this is what get's rendered within a colorbox:

<ul class="horizontal-tabs-list">
  <li class="horizontal-tab-button horizontal-tab-button-0 first selected" tabindex="-1">
    <a href="#">
      <strong>Hide A</strong>
      <span class="summary"></span>
      <span id="active-horizontal-tab" class="element-invisible">(aktiver Reiter)</span>
    </a>
  </li>
  <li class="horizontal-tab-button horizontal-tab-button-1" tabindex="-1">
    <a href="#">
      <strong>Hide B</strong>
      <span class="summary"></span>
    </a>
  </li>
  <li class="horizontal-tab-button horizontal-tab-button-2 last" tabindex="-1">
    <a href="#">
      <strong>Hide C</strong>
      <span class="summary"></span>
    </a>
  </li>
</ul>

Thanks for any hints pointing me somewhere :)