No last changed on an input_boolean helper?

I am trying to write an automation that references the last_changed state of a input_boolean helper, however, the result of the template is alway none.

Example template is:

{% for entity in label_entities("Interface Helper") %}
{% if is_state(entity, 'on') %}
{{entity}}
{{states.entity['last_changed'] }}
{% endif %}
{% endfor %}

entity above reports correctly. However {{states.entity[‘last_changed’] }} is reporting none. If I sub in the full input_boolean entity id, it still has none, however a non-helper devices shows last changed correctly.

Do the helpers have access to last_changed and I am just configuring wrong? or can this not be accessed?

Use the bracket notation for the variable too:

{% for entity in label_entities("Interface Helper") %}
  {%- if is_state(entity, 'on') %}
    {{ entity }}
    {{ states[entity]['last_changed'] }}
  {%- endif %}
{%- endfor %}

Thank you! Works perfectly!