We have fixed the issue. Our template was based on slick. We compared this to Persona and found differences:
In Slick:
<li component="user/logout"> <a href="#"><i class="fa fa-fw fa-sign-out"></i><span> [[global:logout]]</span></a> </li>In Persona:
<li component="user/logout"> <form method="post" action="{relative_path}/logout"> <input type="hidden" name="_csrf" value="{config.csrf_token}"> <input type="hidden" name="noscript" value="true"> <button type="submit" class="btn btn-link"> <i class="fa fa-fw fa-sign-out"></i><span> [[global:logout]]</span> </button> </form> </li>
