Whenever the last_changed of an entity is too old, the graph card line does not load:

Notice that it is able to load the data in the number on the top right (sensor.p1_meter_peak_demand_current_month).
When I plot the history of the data, and download it as CSV I notice the last_changed is old of that one sensor (sensor.p1_meter_peak_demand_current_month)

When I manually set the sensor value, the graph shows again

The configuration of the card:

type: custom:mini-graph-card
name: Peak power
entities:
  - entity: sensor.p1_meter_average_demand
    name: Avg peak now
    show_legend: false
    show_points: false
   
  # entry with an old last_changed
  - entity: sensor.p1_meter_peak_demand_current_month
    show_state: true
    show_legend: false
    show_points: false
    fixed_value: true
  
hours_to_show: 0.25
points_per_hour: 360
aggregate_func: max