Overriding seomatic.meta.robots value has no effect on <meta> tag (in production environment)

[fthues]

I'm conditionally setting seomatic.meta.robots to none like so whenever a certain query variable is set:

  {% if craft.app.request.getQueryParam('r') %}
    {% do seomatic.meta.robots('none') %}
  {% endif %}

I know the condition is working because the HTTP header x-robots-tag does change (from all to none). However, the generated meta tag stays the same:

<meta name="robots" content="all">

I'm not doing anything out of the ordinary configuration wise.