Unhandled Promise rejection at start up

[Hawkeye64]

I have been having an issue for quite some time now but just haven’t had time to follow up on it. At start up of the web app I get the following error:

Error: null
quasar.mat.esm.js:1031
    at this$1.showPromiseReject (webpack-internal:///./node_modules/quasar-framework/dist/quasar.mat.esm.js:1187:10)
    at hide (webpack-internal:///./node_modules/quasar-framework/dist/quasar.mat.esm.js:1201:31)
    at (anonymous) (webpack-internal:///./node_modules/quasar-framework/dist/quasar.mat.esm.js:1144:39)
    at (anonymous) (webpack-internal:///./node_modules/vue/dist/vue.runtime.esm.js:1832:11)
    at flushCallbacks (webpack-internal:///./node_modules/vue/dist/vue.runtime.esm.js:1753:13)

which is this code segment inside methods: of var ModelToggleMixin:

      this.showPromise = new Promise(function (resolve, reject) {
        this$1.showPromiseResolve = function () {
          this$1.showPromise = null;
          this$1.$emit('show', evt);
          resolve(evt);
        };
        this$1.showPromiseReject = function () {
          this$1.showPromise = null;
          reject(null); // eslint prefer-promise-reject-errors: 0
        };
      });

I am absolutely clueless as to why this is happening. Has anyone had issue similar to this and resolve it?