Toolbar1 and Dropdown2 do not integrate properly

When a Toolbar1 button is pressed and it should open a Dropdown2, the button has blue text and a white icon.

See this example: https://codepen.io/chrisdarroch/pen/BmxKKw

The incorrectly styled element state looks like the following:

<a href="#" aria-haspopup="true" class="toolbar-trigger aui-button aui-style-default aui-dropdown2-trigger aui-dropdown2-active" ...>
  <span class="icon aui-icon aui-icon-small aui-iconfont-more"></span>
  <span class="dropdown-text"></span>
</a>

Expected result

The button should behave like a typical AUI button: the background should be dark, and the text and icon should be white.