Why modify the value of two rows with v-model in a v-for with vuejs

I have a classic v-for in vue, to iterate some elements (products) inside it, I want to modify the attribute of this object, but if I do it, it changes in all the rows that have that product

This is the example I have, to add basically I do a push.

<tr v-for="(row, index) in form.items" :key="index">    
      <input type="text" v-model="row.item.description"  class="form-control" v-show="row.edit"
            @blur="row.edit= ! row.edit;"
            :key="index"/>

how could you tell vue that the v-model change be done only on the row that is being modified?