Universal media player - how to update attribute dynamically

Configuration
1

I am using the universal media player integration to control an AmpliPi. I have defined the state attribute of the ump with a template sensor.

When I click on “play” or “stop”, the state of the ump changes (as does the template sensor). However, when I select a different source, although the template sensor reflects the change, the state of the ump is not updated.

Is there a service that I should be calling to update the state of the ump?

sensory.yaml

- platform: template
  sensors:
    amplipi_state:
      value_template: >
          {% if is_state_attr('media_player.office', 'source', 'Source 1') %}
            {{ states('media_player.source_1') }}
          {% elif is_state_attr('media_player.office', 'source', 'Source 2') %}
            {{ states('media_player.source_2') }}
          {% elif is_state_attr('media_player.office', 'source', 'Source 3') %}
            {{ states('media_player.source_3') }}
          {% else %}
            {{ states('media_player.source_4') }}
          {% endif %}

media_player.yaml

- platform: universal
  name: Test
  children:
    - media_player.office
    - media_player.source_2
  commands:
    select_source:
      service: script.amplipi_change_source
      data_template:
        source: "{{ source }}"
  attributes:
    is_volume_muted: media_player.office|is_volume_muted
    state: sensor.amplipi_state
    source: input_select.amplipi_sources
    source_list: input_select.amplipi_sources|options
    volume_level: media_player.office|volume_level

scripts.yaml

amplipi_change_source:
  sequence:
    - service: input_select.select_option
      data_template:
        entity_id: input_select.amplipi_sources
        option: >
            {{ source }}
    - service: media_player.select_source
      data_template:
        entity_id: media_player.office
        source: >
            {% set mapper = {
                'CBC Radio 1': 'Source 1',
                'CBC Music': 'Source 2',
                'AirPlay': 'Source 3',
                'Spotify': 'Source 4' } %}
            {{ mapper[source] if source in mapper else 'Source 1' }}