Vuetify Data Table does not reload on state update - vue.js

Question

I would like to kindly ask you about Vuetify and its Data Table. I am using Vuex for state managing. When I open the page Vuex loads all the data from API. It works perfectly. Then I have the Data Table which also works (update, add, delete), but only one column does not... Data Table is filled with GET_CENTERS and the "one column" is an object (center.customer). When I change center.customer.name state is updated, database is updated, but the value in Data Table is not. (I have tried to just create a list of customers on same page and this list changes if :key is set).
CentersTable
<template>
<div>
<v-data-table
:headers="headers"
:items="GET_CENTERS"
sort-by="name"
class="elevation-1"
>
<template v-slot:top>
<v-toolbar flat color="white">
<v-toolbar-title>My CRUD</v-toolbar-title>
<v-divider
class="mx-4"
inset
vertical
></v-divider>
<div class="flex-grow-1"></div>
<v-dialog v-model="dialog" max-width="500px">
<template v-slot:activator="{ on }">
<v-btn color="primary" dark class="mb-2" v-on="on">Nový Záznam</v-btn>
</template>
<v-card>
<v-card-title>
<span class="headline">{{ formTitle }}</span>
</v-card-title>
<v-card-text>
<v-container>
<v-row>
<v-col cols="12" sm="6" md="6">
<v-text-field v-model="editedItem.name" label="Název"></v-text-field>
</v-col>
<v-col cols="12" sm="6" md="6">
<v-text-field v-model="editedItem.address" label="Adresa"></v-text-field>
</v-col>
<v-col cols="12" sm="6" md="6">
<v-text-field v-model="editedItem.city" label="Město"></v-text-field>
</v-col>
<v-col cols="12" sm="6" md="6">
<v-text-field v-model="editedItem.zip" label="PSČ"></v-text-field>
</v-col>
<v-col cols="12" sm="6" md="6">
<v-text-field v-model="editedItem.email" label="Email"></v-text-field>
</v-col>
<v-col cols="12" sm="6" md="6">
<v-text-field v-model="editedItem.phone" label="Telefon"></v-text-field>
</v-col>
<v-col cols="12" sm="12" md="12">
<v-combobox
v-model="editedItem.customer"
:items="GET_CUSTOMERS"
:search-input.sync="search"
item-text="name"
item-value="_id"
:hide-selected="hideSelected"
label="Zákazník"
persistent-hint
:clearable="clearable"
return-object
>
<template v-if="noData" v-slot:no-data>
<v-list-item>
<v-list-item-content>
<v-list-item-title>
No results matching "<strong>{{ search }}</strong>". Press <kbd>enter</kbd> to create a new one
</v-list-item-title>
</v-list-item-content>
</v-list-item>
</template>
</v-combobox>
</v-col>
</v-row>
</v-container>
</v-card-text>
<v-card-actions>
<div class="flex-grow-1"></div>
<v-btn color="blue darken-1" text #click="close">Cancel</v-btn>
<v-btn color="blue darken-1" text #click="save">Save</v-btn>
</v-card-actions>
</v-card>
</v-dialog>
</v-toolbar>
</template>
<template v-slot:item.action="{ item }">
<v-icon
small
class="mr-2"
#click="editItem(item)"
>
edit
</v-icon>
<v-icon
small
#click="deleteItem(item)"
>
delete
</v-icon>
</template>
</v-data-table>
<template>
<v-list-item v-for="item in GET_CUSTOMERS" :key="item._id">
<v-list-item-content>{{item}}</v-list-item-content>
</v-list-item>
</template>
</div>
</template>
<script>
import {mapActions, mapGetters} from 'vuex'
export default {
name: "CentersTable",
data: () => ({
dialog: false,
editedItem: {},
headers: [
{
text: 'Název',
align: 'left',
sortable: true,
value: 'name',
},
{
text: 'Adresa',
sortable: true,
value: 'address',
},
{
text: 'Město',
sortable: true,
value: 'city',
},
{
text: 'PSČ',
sortable: true,
value: 'zip',
},
{
text: 'Email',
sortable: true,
value: 'email',
},
{
text: 'Telefon',
sortable: true,
value: 'phone',
},
{
text: 'Zákazník',
sortable: true,
value: 'customer.name',
},
{ text: 'Akce', value: 'action', sortable: false, align: 'right' },
],
search: null,
chips: true,
multiple: true,
hideSelected: true,
noData: true,
clearable: false,
}),
watch: {
dialog (val) {
val || this.close()
},
},
computed: {
formTitle() {
return this.editedItem._id === undefined ? 'Nový Záznam' : 'Upravit Záznam'
},
...mapGetters([
'GET_CUSTOMERS',
'GET_CENTERS'
]),
},
methods: {
...mapActions([
'createCenter',
'updateCenter',
'deleteCenter',
]),
editItem (item) {
this.editedItem = Object.assign({}, item)
this.dialog = true
},
deleteItem (item) {
confirm('Opravdu chcete smazat tento záznam?') && this.deleteCenter(item).then(() => {
this.$noty.success('Záznam byl smazán')
}).catch(() => {
this.$noty.alert('Při mazání záznamu došlo k chybě')
})
},
close () {
this.dialog = false
this.editedItem = {}
setTimeout(() => {
}, 300)
},
save () {
if (this.editedItem._id === undefined) {
this.createCenter(this.editedItem).then(() => {
this.$noty.success('Nový zákazník byl vytvořen')
}).catch(() => {
this.$noty.alert('Při vytváření zákazníka došlo k chybě')
})
} else {
this.updateCenter(this.editedItem).then(() => {
this.$noty.success('Záznam byl upraven')
}).catch(() => {
this.$noty.alert('Při ukládání záznamu došlo k chybě')
})
}
this.close()
},
}
}
</script>
<style scoped>
</style>
And Vuex store
import axios from "axios";
import Vue from "vue";
const state = {
customers: []
};
const mutations = {
SET_CUSTOMERS(state, payload) {
state.customers = payload;
},
UPDATE_CUSTOMER(state, payload) {
const customer = state.customers.findIndex(x => x._id === payload._id);
Vue.set(state.customers, customer, payload);
},
ADD_CUSTOMER(state, payload) {
state.customers.push(payload);
},
REMOVE_CUSTOMER(state, payload) {
const customer = state.customers
.map(customer => customer._id)
.indexOf(payload);
state.customers.splice(customer, 1);
}
};
const actions = {
loadCustomers({ commit }) {
axios.get("/api/customers").then(data => {
commit("SET_CUSTOMERS", data.data);
});
},
updateCustomer({ commit }, payload) {
axios.put(`/api/customers/${payload._id}`, payload).then(response => {
commit("UPDATE_CUSTOMER", response.data);
});
},
createCustomer({ commit }, payload) {
axios.post("/api/customers", payload).then(data => {
commit("ADD_CUSTOMER", data.data);
});
},
deleteCustomer({ commit }, payload) {
axios.delete(`/api/customers/${payload._id}`).then(() => {
commit("REMOVE_CUSTOMER", payload);
});
}
};
const getters = {
GET_CUSTOMERS: state => state.customers
};
export default {
state,
mutations,
actions,
getters
};