custom entity rows don't render attributes as expected

[jahopki]

When I apply custom:template-entity-row to an entity (row) in the collection of entities in a custom:timer-bar-card, the custom:template-entity-row.secondary property doesn't render..

Your card configuration

type: vertical-stack
title: secondary display example
cards:
  - type: entities
    entities:
      - type: custom:template-entity-row
        entity: sensor.sun_next_setting
        name: Sunset
        secondary: >-
          {{ as_timestamp(state_attr('sun.sun','next_setting')) |
          timestamp_custom('%I:%M %p') }}
      - type: custom:timer-bar-card
        entities:
          - entity: sun.sun
            type: custom:template-entity-row
            secondary: >-
              {{ as_timestamp(state_attr('sun.sun', 'next_setting')) |
              timestamp_custom('%I:%M %p') }}
            mushroom: null
            name: Sunset
            icon: mdi:weather-sunset-down
            active_state: above_horizon
            end_time:
              attribute: next_setting
            text_width: 5em
            bar_radius: 4px
          - entity: sensor.next_dusk_sensor
            name: Next Dusk
          - entity: sensor.sun_next_setting
            name: Next Setting
            type: custom:template-entity-row
            secondary: >
              "{{ as_timestamp(state_attr('sun.sun', 'next_setting'))|
              timestamp_custom('%I:%M %p') }}"

Debug information The first row in the parent entities collection properly displays the secondary attribute (the current time -- "8:41 PM" in my screen shot); none of rows within the custom:timer-bar-card entities array render the secondary attribute.