Sensor card not showing any detail

I have a template sensor, that I use to calculated the weighted average from some thermometers:

template:
  sensor:
    - name: atc_temperature
      unit_of_measurement: "°C"
      state: >
        {% set n=0 %}
        {% set t=0 %}
        {% if is_state('input_boolean.atc1', 'on') and not is_state('sensor.atc1_temperature', 'unavailable') %} {% set n=n+1 %} {% set t=t+(states('sensor.atc1_temperature') | float ) %} {% endif %}
        {% if is_state('input_boolean.atc2', 'on') and not is_state('sensor.atc2_temperature', 'unavailable') %} {% set n=n+1 %} {% set t=t+(states('sensor.atc2_temperature') | float ) %} {% endif %}
        {% if is_state('input_boolean.atc3', 'on') and not is_state('sensor.atc3_temperature', 'unavailable') %} {% set n=n+1 %} {% set t=t+(states('sensor.atc3_temperature') | float ) %} {% endif %}
        {% if is_state('input_boolean.atc4', 'on') and not is_state('sensor.atc4_temperature', 'unavailable') %} {% set n=n+1 %} {% set t=t+(states('sensor.atc4_temperature') | float ) %} {% endif %}
        {% if is_state('input_boolean.atc5', 'on') and not is_state('sensor.atc5_temperature', 'unavailable') %} {% set n=n+1 %} {% set t=t+(states('sensor.atc5_temperature') | float ) %} {% endif %}
        {% if is_state('input_boolean.atc6', 'on') and not is_state('sensor.atc6_temperature', 'unavailable') %} {% set n=n+1 %} {% set t=t+(states('sensor.atc6_temperature') | float ) %} {% endif %}
        {% if is_state('input_boolean.atc7', 'on') and not is_state('sensor.atc7_temperature', 'unavailable') %} {% set n=n+1 %} {% set t=t+(states('sensor.atc7_temperature') | float ) %} {% endif %}
        {% if is_state('input_boolean.atc8', 'on') and not is_state('sensor.atc8_temperature', 'unavailable') %} {% set n=n+1 %} {% set t=t+(states('sensor.atc8_temperature') | float ) %} {% endif %}
        {% if (n > 0) %} {{ (t / n) | float }} {% endif %}

Now, I have a sensor card, that I use to display this sensor:

type: sensor
entity: sensor.atc_temperature
icon: mdi:thermometer
unit: ºC
detail: 2
name: Temperatura
graph: line

What I see on this card is this:
Screenshot-20210925233609-498x253
(notice how the temperature seems to be very stable)

However, when clicking on that card, this other image pops-up:
Screenshot-20210925233647-404x359
(notice the amount of detail, and the variation in temperature)

What am I doing wrong? Why is the card not showing any detail at all?

Set the y axis limits to 24 and 26. Set detail to 2.

Ok, so that seems to fix the display.l, thanks!

But shouldn’t this be done automatically (at least, that is what the documentation says)? It does not seems reasonable having to know the min and max temperatures when configuring the card.

Perhaps there is something wrong with my template sensor? Or is there another card more suited for this info?

Many thanks!

I find the custom mini-graph-card works well.

If you believe the card is not working in accordance with the docs, please file an issue on github.