Vuex - Vuelidate - set :value once

Hey guys,
I have difficulties to apply a simple form validation using vuelidate. To describe my specific problem i prepared this little fiddle for you.

https://jsfiddle.net/felix1337/hxLd7j21/2/

I am using vuex to store my data and connect the vuex-store with my component via the mapState - function. I load the stored data into the input field via value-binding (:value). I want the value binding applied only once,.But the value of the input field is reseted to its initial store-state value while typing. Is there a way to bypass this? I really would like to use the computed property for this app.

Thank you so much.

@felix1337 Please used v-once Directive

Example:
<input type=“text” v-once :value=“student.firstname” id=“firstname” @input=“updateLocal($event)”/>

for more information refer official vue.js document: https://vuejs.org/v2/guide/syntax.html