I found a solution. I add a listener
@shown="hidePopup"

hidePopup is a mixin
export default {
methods: {
hidePopup(e) {
setTimeout(() => {e.target.classList.remove('show')}, 2000);
}
}
};

in main.js
import hidePopup from '@/mixins/hidePopup.js'
app.mixin(hidePopup);