Different results using cypress:open and cypress:run - why?

[tiec7]

I have this simple page (a notfound page) in vue2 (but it's simple plain HTML):

NotFound.vue

<template>
  <section>
    <base-card>
      <h2 id="notFoundTitle">This isn't the page you are looking for.</h2>

      <p>
        404 - This page could not be found - check out all our
        <router-link to="/coaches">coaches</router-link>
      </p>
    </base-card>
  </section>
</template>

now i created this simple test in Cypress:

notLogged.cy.js

let siteUrl = 'https://my.site/'

describe('Tests for pages without login', () => {
  describe('Tests for the home page', () => {
   
    it('Tests the not found page', async () => {
      let url = siteUrl + '/stuff'

      cy.visit(url)
      let pageTitle = cy.get('#notFoundTitle')
      let pagePar = cy.get('p')

      expect(pageTitle).to.exist
      expect(pagePar).to.exist

      pageTitle.should('have.text', "This isn't the page you are looking for.")
      pagePar.should('contain', '404')
    })
  })
})

my package.json file is:

{
  "name": "test_cy",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "type": "module",
  "scripts": {
    "cypress:open": "cypress open",
    "cypress:run": "cypress run notLogged.cy.js"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "cypress": "^13.6.3"
  }
}

When I run npm run cypress:run everything works fine and says that the 2 tests have passed.
BUT when I run npm run cypress:open and i use chrome for e2e testing, it throws an absurd error, shown in image:

and this doesn't makes absolutely ANY sense, since i am not searching for 'p' and 'have.text' !

Does someone have an idea why?