Why is this data corrupt?

I seem to have an issue with one of my weather forecast cards. I am plotting various weather forecast items like this:


And as you can see, the UV index is corrupted. It was working fine just a few moments ago.

In the inspection in developer tools, the attributes look fine:

I get this error in the logs, but I think that just means recorder will not store this data:

That’s fine… I don’t need it stored…

I cannot figure out why the UV index chart is corrupt, the code is literally the same as all the other charts:

type: custom:apexcharts-card
graph_span: 8d
experimental:
  color_threshold: true
show:
  last_updated: true
span:
  start: day
header:
  show: true
  title: Hourly UV Index Forecast
  show_states: true
  colorize_states: true
now:
  show: true
  color: red
  label: Now
series:
  - entity: sensor.pirate_weather_hourly
    name: UV Index
    data_generator: |
      return entity.attributes.forecast.map(forecast => {
        return [new Date(forecast.datetime).getTime(), forecast.uv_index];
      });
    color_threshold:
      - value: 0
        color: steelblue
      - value: 11
        color: red
    show:
      extremas: true
chart_type: line
yaxis:
  - min: 0
    max: 12

Any ideas??? How can I debug this. I tried deleting and remaking the card, and I get the same thing

Ah crap, nevermind… the data itself is coming in from pirate weather corrupt… I will add a filter to the chart to discard values over 13…