vue.js Uncaught (in promise) Error: ERR_ACTION_ACCESS_UNDEFINEDエラー解決方法

Question

test.jsonの値をgroupEntitiesに保存したいのですが下記のエラーになってしまいます。

処理内容としてはgroupPageにアクセスした時に、created()の中のgroupStore.loadGroup()が呼ばれて、
その中のthis.addGroup(test)が呼ばれます。
addGroup()の中の
this.groupEntities = [...this.groupEntities, new GroupEntity(group)]でjsonのデータを保存しています。

// groupPage
<template>
  <div class="center-column">
    {{ groupStore.groupEntity.count }}
    {{ groupStore.groupEntity.type }}
    {{ groupStore.groupEntity.selections[0] }}
  </div>
</template>
<script lang="ts">
import { Component, Vue } from 'vue-property-decorator'
import { grouprStore } from '@/store/'
@Component
export default class GroupPage extends Vue {
  created() {
    groupStore.loadGroup()
  }
}
</script>

 //store
import { VuexModule, Module, Mutation, Action } from 'vuex-module-decorators'
import { Group } from '../domain/test.ts';
import test from '@/assets/test.json'
export class GroupEntity {
  type: string = ''
  count: number = 0
  selections: Statuse[] = []

  constructor(group: Group) {
    this.type = group.member.type
    this.count = group.count
    this.selections = this.addSelections(group.member.statuse.selection)
  }
  private addSelections(selections: Selections[]) {
    let select: any = []
    selections.forEach((selection) => {
      select = selection
    })
    return select
  }
}
export interface IGroupState {
  groupEntities: GroupEntity[]
}
@Module({ stateFactory: true, namespaced: true, name: 'groups' })
export default class Groups extends VuexModule implements IGroupState {
  groupEntities: GroupEntity = []

  @Mutation
  addGroup(group: Group) {
    this.groupEntities = [...this.groupEntities, new GroupEntity(group)]

  @Action
   loadGroup() {
      this.addGroup(test)
  }
 }   

//test.ts
export class Group {
  count: number = 0
  member = Member
}
export class Member {
  type: ''
  status = Statuse
}
export class Statuse {
  selection  =  Selection[]
}
export class Selection {
  id: number = 0
  name: string = ''
}

// test.jspn
{
  "count": 3,
  "member": [
    {
      "type": "groupA",
      "statuse": {
        "selection": [
            {
                "id": 0,
                "name": "hello world"
            }, {
                "id": 1,
                "name": "hello world two"
            }
        ]
      }
    }
  ]
}

// エラーメッセージ
index.js?6fc5:353 Uncaught (in promise) Error: ERR_ACTION_ACCESS_UNDEFINED: Are you trying to access this.someMutation() or this.someGetter inside an @Action? 
That works only in dynamic modules. 
If not dynamic use this.context.commit("mutationName", payload) and this.context.getters["getterName"]
Error: Could not perform action loadCareers
    at Store.eval (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:366:37)
    at step (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:135:23)
    at Object.eval [as next] (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:116:53)
    at eval (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:109:71)
    at new Promise (<anonymous>)
    at __awaiter (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:105:12)
    at Store.action (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:326:20)
    at Array.wrappedActionHandler (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:755:23)
    at Store.dispatch (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:446:15)
    at Store.boundDispatch [as dispatch] (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:340:21)
TypeError: Cannot read property 'selections' of undefined
    at new CareerEntity (webpack-internal:///./store/career.ts:57:73)
    at Object.addCareer (webpack-internal:///./store/career.ts:93:155)
    at Store.mutation (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:427:26)
    at wrappedMutationHandler (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:748:13)
    at commitIterator (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:400:7)
    at Array.forEach (<anonymous>)
    at eval (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:399:11)
    at Store._withCommit (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:530:3)
    at Store.commit (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:398:8)
    at Store.boundCommit [as commit] (webpack-internal:///./node_modules/vuex/dist/vuex.esm.js:343:19)
    at Store.eval (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:360:35)
    at step (webpack-internal:///./node_modules/vuex-module-decorators/dist/esm/index.js:135:23)
    at Object.eval [as next] (webpack-internal:///./node_modules/vuex-module-