Template sensor dependency

I have a template light depending on another template binary sensor.
The former entity generates an error whenever template entities configuration reloads.

Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/entity_platform.py", line 598, in _async_add_entities
    await coro
  File "/usr/src/homeassistant/homeassistant/helpers/entity_platform.py", line 912, in _async_add_entity
    await entity.add_to_platform_finish()
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 1365, in add_to_platform_finish
    await self.async_added_to_hass()
  File "/usr/src/homeassistant/homeassistant/components/template/template_entity.py", line 545, in async_added_to_hass
    async_at_start(self.hass, self._async_template_startup)
  File "/usr/src/homeassistant/homeassistant/helpers/start.py", line 71, in async_at_start
    return _async_at_core_state(
           ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/start.py", line 36, in _async_at_core_state
    hass.async_run_hass_job(at_start_job, hass)
  File "/usr/src/homeassistant/homeassistant/core.py", line 938, in async_run_hass_job
    hassjob.target(*args)
  File "/usr/src/homeassistant/homeassistant/components/template/template_entity.py", line 486, in _async_template_startup
    result_info.async_refresh()
  File "/usr/src/homeassistant/homeassistant/helpers/event.py", line 1108, in async_refresh
    self._refresh(None)
  File "/usr/src/homeassistant/homeassistant/helpers/event.py", line 1294, in _refresh
    self.hass.async_run_hass_job(self._job, event, updates)
  File "/usr/src/homeassistant/homeassistant/core.py", line 938, in async_run_hass_job
    hassjob.target(*args)
  File "/usr/src/homeassistant/homeassistant/components/template/template_entity.py", line 430, in _handle_results
    template_attr.handle_result(
  File "/usr/src/homeassistant/homeassistant/components/template/template_entity.py", line 217, in handle_result
    self.on_update(result)
  File "/usr/src/homeassistant/homeassistant/components/template/light.py", line 712, in _update_effect
    if effect not in self._effect_list:
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: argument of type 'NoneType' is not iterable


The problem only happens when loading and it works any other time.
I have added event_template_reloaded trigger but it does not work.
How could I update the template to avoid the error message?
Here is the simplified configuration of both template entities:

- platform: template
  lights:
    bedroom_light_effect:
      value_template: "{{ states('light.bedroom_light') }}"
      effect_list_template: "{{ state_attr('binary_sensor.light_effect', 'options') }}"
      effect_template: "{{ 'Holiday' if is_state('binary_sensor.light_effect','on') else 'Nothing' }}"

- trigger:
    - id: other-triggers
      ...
    - id: reload
      platform: event
      event_type: event_template_reloaded
  binary_sensor:
    - name: Light effect
      state: "..."
      attributes:
        options: "{{ ['Nothing', 'Holiday'] }}"

The effect list isn’t initialized yet when the light loads. Either put a default in at the light template or hard code the effects there too if the list never changes.