Not able to generate deeply nested embed forms

I am trying to use two nested inputs_for with no success. Essentially, I have this (abbreviated for simplicity):

# CalendarApp.Calendars.Calendar
  schema "calendars" do
    ...
    # In the migration I have "add :working_hours, :map"
    embeds_many :working_hours, WorkingHour, on_replace: :delete
  end

# CalendarApp.Calendars.WorkingHour
  embedded_schema do
    ...
    embeds_many :time_intervals, TimeInterval, on_replace: :delete
  end

# CalendarApp.Calendars.TimeInterval
  embedded_schema do
    ...
    # no more embeds
  end

My object

%CalendarApp.Calendars.Calendar{
  __meta__: #Ecto.Schema.Metadata<:loaded, "calendars">,
  id: 1,
  working_hours: [
    %CalendarApp.Calendars.WorkingHour{
      id: "c8140693-be33-4f50-a087-653ce92fa3be",
      weekday: :Sunday,
      enabled: false,
      time_intervals: [
        %CalendarApp.Calendars.TimeInterval{
          id: "0d31837a-d295-4d7b-984f-edfe18858f70",
          start_time: ~T[08:00:00],
          end_time: ~T[12:00:00]
        },
        %CalendarApp.Calendars.TimeInterval{
          id: "e11b03a4-75be-4067-b477-733ebea6b31c",
          start_time: ~T[13:00:00],
          end_time: ~T[18:00:00]
        }
      ]
    },
    %CalendarApp.Calendars.WorkingHour{
      id: "a5a70b7e-577a-42b0-a2f7-4d396c3cd3ad",
      weekday: :Monday,
      enabled: true,
      time_intervals: [
        %CalendarApp.Calendars.TimeInterval{
          id: "865aeea2-d234-47c1-aa1d-b8655c2909f7",
          start_time: ~T[08:00:00],
          end_time: ~T[12:00:00]
        },
        %CalendarApp.Calendars.TimeInterval{
          id: "f80e3863-b801-4964-8c71-f7fca7d567ba",
          start_time: ~T[13:00:00],
          end_time: ~T[18:00:00]
        }
      ]
    },
    ...
  ]
}

how I am trying to present this data

<%= for whf <- inputs_for(f, :working_hours) do %>
  <li class="pb-4 flex items-center justify-between">
    <%= hidden_inputs_for(whf) %>
    <%= label whf, :weekday, class: "text-base font-medium text-gray-900" do %>
      <%= whf.data.weekday %>
    <% end %>
    <%= for intf <- inputs_for(whf, :time_intervals) do %>
      <%= hidden_inputs_for(intf) %>
      <% time_input intf, :start_time %>
      <% time_input intf, :end_time %>
    <% end %>
    <%= error_tag whf, :weekday %>
  </li>
<% end %>

Just the labels and the hidden fields are being rendered

image1014×630 9.61 KB

<ul role="list">
  <li class="pb-4 flex items-center justify-between">
    <input id="calendar_working_hours_0_id" name="calendar[working_hours][0][id]" type="hidden" value="c8140693-be33-4f50-a087-653ce92fa3be">
    <label class="text-base font-medium text-gray-900" for="calendar_working_hours_0_weekday">
    Sunday
    </label>
    <input id="calendar_working_hours_0_time_intervals_0_id" name="calendar[working_hours][0][time_intervals][0][id]" type="hidden" value="0d31837a-d295-4d7b-984f-edfe18858f70">
    <input id="calendar_working_hours_0_time_intervals_1_id" name="calendar[working_hours][0][time_intervals][1][id]" type="hidden" value="e11b03a4-75be-4067-b477-733ebea6b31c">
  </li>
  <li class="pb-4 flex items-center justify-between">
    <input id="calendar_working_hours_1_id" name="calendar[working_hours][1][id]" type="hidden" value="a5a70b7e-577a-42b0-a2f7-4d396c3cd3ad">
    <label class="text-base font-medium text-gray-900" for="calendar_working_hours_1_weekday">
    Monday
    </label>
    <input id="calendar_working_hours_1_time_intervals_0_id" name="calendar[working_hours][1][time_intervals][0][id]" type="hidden" value="865aeea2-d234-47c1-aa1d-b8655c2909f7">
    <input id="calendar_working_hours_1_time_intervals_1_id" name="calendar[working_hours][1][time_intervals][1][id]" type="hidden" value="f80e3863-b801-4964-8c71-f7fca7d567ba">
  </li>
  ...
</ul>

I’ve tried many different fields and structures for this form but without success. Does anyone know if this is even possible?