Vaadin 14 - Application breaking on dropdown-menu?

Flow
1

When I try to start my application, the layout is destroyed and there seems to be a conflict in the npm modules, as the console shows:

Uncaught DOMException: Failed to execute 'define' on 'CustomElementRegistry': the name "dom-module" has already been used with this registry
    at eval (webpack-internal:///../node_modules/@polymer/paper-dropdown-menu/node_modules/@polymer/polymer/lib/elements/dom-module.js?babel-target=es6:181:16)
    at Module.../node_modules/@polymer/paper-dropdown-menu/node_modules/@polymer/polymer/lib/elements/dom-module.js?babel-target=es6 (http://localhost:8088/VAADIN/build/vaadin-bundle-819c19c73ff74dc82dd2.cache.js:625:1)
    at __webpack_require__ (http://localhost:8088/VAADIN/build/vaadin-bundle-819c19c73ff74dc82dd2.cache.js:20:30)
    at eval (webpack-internal:///../node_modules/@polymer/paper-dropdown-menu/node_modules/@polymer/polymer/lib/utils/style-gather.js?babel-target=es6:10:81)
    at Module.../node_modules/@polymer/paper-dropdown-menu/node_modules/@polymer/polymer/lib/utils/style-gather.js?babel-target=es6 (http://localhost:8088/VAADIN/build/vaadin-bundle-819c19c73ff74dc82dd2.cache.js:1021:1)
    at __webpack_require__ (http://localhost:8088/VAADIN/build/vaadin-bundle-819c19c73ff74dc82dd2.cache.js:20:30)
    at eval (webpack-internal:///../node_modules/@polymer/paper-dropdown-menu/node_modules/@polymer/polymer/lib/mixins/element-mixin.js?babel-target=es6:8:80)
    at Module.../node_modules/@polymer/paper-dropdown-menu/node_modules/@polymer/polymer/lib/mixins/element-mixin.js?babel-target=es6 (http://localhost:8088/VAADIN/build/vaadin-bundle-819c19c73ff74dc82dd2.cache.js:733:1)
    at __webpack_require__ (http://localhost:8088/VAADIN/build/vaadin-bundle-819c19c73ff74dc82dd2.cache.js:20:30)
    at eval (webpack-internal:///../node_modules/@polymer/paper-dropdown-menu/node_modules/@polymer/polymer/lib/legacy/legacy-element-mixin.js?babel-target=es6:4:82)

It seems that the polymer version could be the problem:
package-lock.json states that

    "@polymer/paper-dropdown-menu": {
      "version": "3.1.0",
      "dependencies": {
        "@polymer/polymer": {
          "version": "3.3.1",

and package.json states

  "dependencies": {
    "@polymer/polymer": "3.2.0",
2

Found the “offending” addon: [wysiwyg-e Rich Text Editor]
(https://vaadin.com/directory/component/wysiwyg-e-rich-text-editor-component-for-java/overview) version 2.0.0.

Link to the [github issue]
(https://github.com/pleku/wysiwyg-e-java/issues/16).