Vue 3: setup is returning undefined

Question

Im trying to show a Modal if the open prop is true but for some reason Im getting undefined instead of False (Boolean)

<script>
import { ref } from 'vue';
import Modal from '@/components/Modal.vue';

export default {

    components: {
        Modal
    },
    setup() {
        const isOpen = ref(false)
        return { isOpen }
    }
}
</script>

<template>
    <div>
        <Modal :open="isOpen">Some Text</Modal>
    </div>
</template>

This is the error:

[Vue warn]: Invalid prop: type check failed for prop "open". Expected Boolean, got Undefined  
  at <Modal open=undefined onClose=fn > 
  at <Dashboard> 
  at <Developers errors

Im using: Laravel 9, ViteJs, Vue3.