What is causing this to crash the game?

[half parcel]

"hud_title_text": {
    "type": "stack_panel",
    "orientation": "vertical",
    "offset": [ 0, -19 ],
    "layer": 1,
    "alpha": "@hud.anim_title_text_alpha_in",
    "propagate_alpha": true,
    "controls": [
      {
        "title_frame": {
          "type": "panel",
          "size": [ "100%", "100%cm" ],
          "controls": [
            {
              "title_background": {
                "type": "image",
                "size": [ "100%sm + 30px", "100%sm + 6px" ],
                "texture": "textures/ui/hud_tip_text_background",
                "alpha": "@hud.anim_title_background_alpha_in"
              }
            },

            {
              "title": {
                "type": "label",
                "color": "$title_command_text_color",
                "$locality_title_id": "test:locality_title", // Changes start here
                "$atext": "#text",
                "$atext_clone": "$atext - $locality_title_id",
                "text": "$atext_clone",
                "layer": 31,
                "localize": false,
                "font_size": "extra_large",
                "variables": [
                  {
                    "requires": "(not $title_shadow)",
                    "$show_shadow": false
                  },
                  {
                    "requires": "$title_shadow",
                    "$show_shadow": true
                  },
                  {
                    "requires": "not ($atext = $atext_clone)",
                    "$alignment": "right"
                  },
                  {
                    "requires": "$atext = $atext_clone",
                    "$alignment": "center"
                  },
                  {
                    "requires": "not ($atext = $atext_clone)",
                    "$customoffset": [ -6, 12 ]
                  },
                  {
                    "requires": "$atext = $atext_clone",
                    "$customoffset": [ 0, 6 ]
                  }
                ],
                "anchor_from": "top_middle",
                "anchor_to": "top_middle",
                "shadow": "$show_shadow",
                "text_alignment": "$alignment",
                "offset": "$customoffset",
                "bindings": [
                  {
                    "binding_name": "#hud_title_text_string",
                    "binding_name_override": "#text",
                    "binding_type": "global"
                  }
                ]
              }
            }
          ]
        }
      },