Vuetify block UI for a few seconds - vuetify.js

Question

Loading v-for on follow code:
<v-flex class="v-card-cards" xs6 sm4 md4 lg2>
<v-card>
<v-card-title>
<span class="headline black--text">
<v-tooltip bottom>
<template v-slot:activator="{ on }">
<v-btn icon color="warning" flat small v-on="on">
<v-icon>edit</v-icon>
</v-btn>
</template>
<span>{{ $t('messages.app.edit') }}</span>
</v-tooltip>
<v-tooltip bottom>
<template v-slot:activator="{ on }">
<v-btn icon color="error" flat small v-on="on">
<v-icon>delete</v-icon>
</v-btn>
</template>
<span>{{ $t('messages.app.delete') }}</span>
</v-tooltip>
</span>
<v-spacer></v-spacer>
<v-icon class="profile_icon elevation-5 success--text" x-large>account_circle</v-icon>
</v-card-title>
<v-divider class="ml-0"></v-divider>
<v-list>
<v-list-tile>
<v-list-tile-action>
<v-tooltip top>
<template v-slot:activator="{ on }">
<v-icon color="info" small v-on="on">info</v-icon>
</template>
<span>{{ $t('messages.forms.newCard.fields.firstname.label') }}</span>
</v-tooltip>
</v-list-tile-action>
<div>
<span class="caption truncate">{{ item.firstname }}</span>
</div>
</v-list-tile>
<v-divider inset></v-divider>
<v-list-tile>
<v-list-tile-action>
<v-tooltip top>
<template v-slot:activator="{ on }">
<v-icon color="info" small v-on="on">info</v-icon>
</template>
<span>{{ $t('messages.forms.newCard.fields.lastname.label') }}</span>
</v-tooltip>
</v-list-tile-action>
<div>
<span class="caption truncate">{{ item.lastname }}</span>
</div>
</v-list-tile>
<v-divider inset></v-divider>
<v-list-tile>
<v-list-tile-action>
<v-tooltip top>
<template v-slot:activator="{ on }">
<v-icon color="info" small v-on="on">people</v-icon>
</template>
<span>{{ $t('messages.forms.newCard.fields.groups.label') }}</span>
</v-tooltip>
</v-list-tile-action>
<div>
<span
v-for="group in item.groups"
:key="item.groups._id"
class="caption truncate"
>{{ group.description }}</span>
</div>
</v-list-tile>
<v-divider inset></v-divider>
<v-list-tile>
<v-list-tile-action>
<v-tooltip top>
<template v-slot:activator="{ on }">
<v-icon color="info" small v-on="on">note</v-icon>
</template>
<span>{{ $t('messages.forms.newCard.fields.notes.label') }}</span>
</v-tooltip>
</v-list-tile-action>
<div>
<span class="caption truncate">{{ item.notes }}</span>
</div>
</v-list-tile>
<v-divider inset></v-divider>
</v-list>
<v-card-actions class="mx-3">
<v-spacer></v-spacer>
<v-tooltip top>
<template v-slot:activator="{ on }">
<v-badge overlap color="info">
<template v-slot:badge>12</template>
<v-icon
large
v-on="on"
color="grey darken-1"
#click="$router.push({ name: 'dashboard' })"
>description</v-icon>
</v-badge>
</template>
<span>{{ $t('messages.forms.newCard.fields.notes.label') }}</span>
</v-tooltip>
</v-card-actions>
</v-card>
page is blocked for a few seconds, during the loading of this contents. Why? Can resolve? I have tried avoid 'v-' directive of vuetify, using only html and so not get nothing block. But i want use vuetify style.
Have tried to find other similar question on web but i don't find nothing about this argument