Above are two <router-link> tags, with texts rendered by

<router-link class="curly_bracket">{{ $t('curly_bracket') }}</router-link>

and

<router-link class="directive" v-t="'directive'" />

View page source and you can see that only the first one is shown, the second one using directive is now shown...

Refesh this page and you can see that the second line shows a little bit later, too.