When Page Tree Plugin Cannot be encapsulated by any Text Attributes, such as Bold, Italic and more it renders Undefined

Problem

Page Tree Macro does not work when it is wrapped around a text attribute such as bold or italic, it renders Undefined

<p>
  <strong>
    <br/>
  </strong> <strong>
    <ac:macro ac:name="pagetree"/>
  </strong>
</p>

Workaround

Delete the Macro and create it again, make sure that no attribute has been selected.