Обновление Symfony с 4.2 до 4.3 привело к поломке Web Profiler

Я запустил composer update и теперь получаю множество предупреждений об устаревании:

> [2019-06-03 18:08:41] request.INFO: Matched route "_wdt".
> {"route":"_wdt","route_parameters":{"_route":"_wdt","_controller":"web_profiler.controller.profiler::toolbarAction","token":"9354bc"},"request_uri":"http://local
> host:8080/_wdt/9354bc","method":"GET"} [] [2019-06-03 18:08:42]
> request.CRITICAL: Uncaught PHP Exception Twig\Error\RuntimeError:
> "Impossible to access an attribute ("nb_errors") on a string variable
> ("O:39:"Symfony\Component\VarDumper\Cloner\Data":6:{s:45:"ymf
> ony\Component\VarDumper\Cloner\Data

Панель инструментов веб-профилировщика не работает с этой ошибкой:

An error occurred while loading the web debug toolbar.

И все же, когда я это делаю bin/console --version, я получаю:

Symfony 4.3.0 (env: dev, debug: true)

Что дает? А как насчет файла композитор.json, который дает Композитор возможность обновляться даже до 4.3?

Вот мой текущий композитор.json:

{
  "type": "project",
  "license": "proprietary",
  "require": {
    "php": "^7.1.3",
    "ext-iconv": "*",
    "doctrine/doctrine-migrations-bundle": "^2.0",
    "easycorp/easyadmin-bundle": "^1.17",
    "iio/libmergepdf": "~3.0",
    "ramsey/uuid": "^3.5",
    "sensio/framework-extra-bundle": "^5.1",
    "sensiolabs/security-checker": "^5.0",
    "simplisti/jasper-starter": "dev-master",
    "symfony/asset": "4.2.*",
    "symfony/console": "4.2.*",
    "symfony/dotenv": "4.2.*",
    "symfony/expression-language": "4.2.*",
    "symfony/flex": "^1.1",
    "symfony/form": "4.2.*",
    "symfony/framework-bundle": "4.2.*",
    "symfony/ldap": "^4.0",
    "symfony/monolog-bundle": "^3.3",
    "symfony/options-resolver": "^4.0",
    "symfony/orm-pack": "*",
    "symfony/process": "4.2.*",
    "symfony/security-bundle": "4.2.*",
    "symfony/swiftmailer-bundle": "^3.1",
    "symfony/yaml": "4.2.*"
  },
  "require-dev": {
    "doctrine/doctrine-fixtures-bundle": "^3.0",
    "phing/phing": "^2.14",
    "symfony/browser-kit": "^4.0",
    "symfony/css-selector": "^4.0",
    "symfony/debug": "^4.0",
    "symfony/debug-pack": "^1.0",
    "symfony/maker-bundle": "^1.7",
    "symfony/phpunit-bridge": "^4.0",
    "symfony/profiler-pack": "^1.0"
  },
  "config": {
    "preferred-install": {
      "*": "dist"
    },
    "sort-packages": true
  },
  "autoload": {
    "classmap": [
      "src/Legacy/"
    ],
    "psr-4": {
      "App\\": "src/"
    }
  },
  "autoload-dev": {
    "psr-4": {
      "App\\Tests\\": "tests/"
    }
  },
  "replace": {
    "symfony/polyfill-iconv": "*",
    "symfony/polyfill-php71": "*",
    "symfony/polyfill-php70": "*",
    "symfony/polyfill-php56": "*"
  },
  "scripts": {
    "auto-scripts": {
      "cache:clear": "symfony-cmd",
      "assets:install --symlink --relative %PUBLIC_DIR%": "symfony-cmd",
      "security-checker security:check": "script"
    },
    "post-install-cmd": [
      "@auto-scripts"
    ],
    "post-update-cmd": [
      "@auto-scripts"
    ]
  },
  "conflict": {
    "symfony/symfony": "*"
  },
  "extra": {
    "symfony": {
      "id": "01C3XNQSBGC1MSASSGCW6TKGXB",
      "allow-contrib": false
    }
  }
}