Card mod: new version - new problem (cut code)

After entering the sample code:

type: vertical-stack
cards:
  - type: custom:mushroom-template-card
    card_mod:
      style: |
        ha-card {
          --secondary-text-color: black;
          --primary-text-color: black;
          }
        @media (prefers-color-scheme: light) {
          ha-card {
            --ha-card-background: ivory;
          }
        }
        @media (prefers-color-scheme: dark) {
          ha-card {
            --ha-card-background: dimgrey;
          }
        }
    primary: ''
    secondary: Salon
    icon: ''
    layout: vertical
    icon_color: ''
    tap_action:
      action: none
    hold_action:
      action: none
    double_tap_action:
      action: none
  - type: horizontal-stack
    cards:
      - type: custom:mushroom-template-card
        primary: TV
        secondary: ''
        icon: mdi:lamp
        entity: switch.lampa_salon_1
        icon_color: |-
          {% if is_state("switch.lampa_salon_1", "on") %}
                  orange
                {% else %}
                  grey
                {% endif %}
        badge_icon: ''
        badge_color: ''
      - type: custom:mushroom-template-card
        primary: Back
        secondary: ''
        icon: mdi:lamp
        entity: switch.lampa_salon_2
        icon_color: |-
          {% if is_state("switch.lampa_salon_2", "on") %}
                  orange
                {% else %}
                  grey
                {% endif %}
        badge_icon: ''
        badge_color: ''

the buttons look good.
But re-editing always cuts the code

    card_mod:
      style: |
        ha-card {
          --secondary-text-color: black;
          --primary-text-color: black;
          }
        @media (prefers-color-scheme: light) {
          ha-card {
            --ha-card-background: ivory;
          }
        }
        @media (prefers-color-scheme: dark) {
          ha-card {
            --ha-card-background: dimgrey;
          }
        }

The problem occurred after updating card-mod to a new version and adding “card_mod:”

Why is this happening?