Icon in custom:button-card not been retrieved

Hi everyone,

I´ve got the below custom-card, where I´m trying to point the icon to and .svg file.

type: custom:button-card
entity: sensor.weather_info
name: |
  [[[ 
    return states['sensor.blitzwolf_bw_is4_temperature'].state
    + '<span style="font-size:0.6em">°C</span>'
  ]]]
label: |-
  [[[
    return states['weather.openweathermap'].attributes.temperature
    + '<span style="font-size:0.6em">°C</span>'
  ]]]
show_label: true
customs_fields:
  icon: |-
    [[[
      return  '<img src="/local/weather/partlycloudy.svg" width="50" height="50"/>'
    ]]]
styles:
  grid:
    - grid-template-areas: "\"i n\" \"i l\""
  card:
    - overflow: visible
    - background: none
    - padding-right: 8px
  name:
    - justify-self: end
    - font-size: 14px
  label:
    - justify-self: start
    - font-size: 26px
    - font-weight: 500
  customs_fields:
    icon:
      - justify-self: end
      - align-self: end
      - padding-right: 10px
      - margin-bottom: "-11px"

I can´t understand why, but instead of the correct svg image, I get an eye…

eye

For debugging, I tried the exact same code on the label section, and it runs as expected.

label: |-
    [[[
      return  '<img src="/local/weather/partlycloudy.svg" width="50" height="50"/>'
    ]]]

not_eye

Do you have any idea of what I´m missing?
Many thanks,