Custom method casting does not work

<%- if @topic_view.topic.tags.present? %>
<%= t 'js.tagging.tags' %>: <%- @topic_view.topic.tags.each do |t| %> <%= t %> <%- end %>
<% end %>

Silverstripe Version: 4.7.3

Hey *!
I’ve the same situation in my PageController discribed like here:

But this does not work for me: template output is still

&lt;h1&gt;This is my header&lt;/h1&gt;

and NOT

<h1>This is my header</h1>

as “promised” in documentation…

I’ve no idea what goes wrong with it.
Can anyone help me out?

Thank’s in advance!