In v-list-group, the item in sub-group was closed when the page refreshed

[Juliming]

I have a navigation sidebar with nested v-list-group.
I create up to 2 levels in depth using the sub-group property. This works well with the top level v-list-group.It opens up if I reload the page and the route matches the "group" prop.
But in the subgroup, When I reload the page I can see the subgroup closing, so I think the group prop is working. But something is making it close immediately after.
My code:
<v-navigation-drawer
:mini-variant.sync="mini"
app
clipped
width="250"
v-model="drawerState"
background-color="#242327"
dark

<v-list dense nav>
  <template v-for="(item) in menu">
    <v-list-group :key="item.topic" v-if="item.children" :prepend-icon="item.icon" :group="item.group"
                  color="white" style="background: transparent;" active-class="bg-active"
    >
      <template v-slot:activator>
        <v-list-item-title class="textAlignLeft">{{ $t(item.topic) }}</v-list-item-title>
      </template>
      <template v-for="(ch) in item.children">
        <v-list-group v-if="ch.children" :key="ch.topic" sub-group :group="ch.group" class="ml-0 pl-0"
                      color="white" :value="true">
          <template v-slot:activator>
            <v-list-item-title class="textAlignLeft">{{ $t(ch.topic) }}</v-list-item-title>
          </template>
          <v-list-item v-for="(g) in ch.children" :key="g.topic" :to="g.to" class="pl-3" exact>
            <v-list-item-content class="ml-13 pl-2">{{ $t(g.topic) }}</v-list-item-content>
          </v-list-item>
        </v-list-group>
        <v-list-item :key="ch.topic" :to="ch.to" class="pl-3" v-else>
          <v-list-item-content class="ml-13">{{ $t(ch.topic) }}</v-list-item-content>
        </v-list-item>
      </template>
    </v-list-group>
    <v-list-item
        :to="item.to"
        :key="item.topic"
        v-else
    >
      <v-list-item-icon>
        <v-icon>{{ item.icon }}</v-icon>
      </v-list-item-icon>
      <v-list-item-content class="textAlignLeft">{{ $t(item.topic) }}</v-list-item-content>
    </v-list-item>
  </template>
</v-list>
<template v-slot:append>
  <div class="textAlignLeft fontsizegroup">
    <span class="pl-10">{{ userInfo.userName }}</span>
    <v-btn icon @click="logOut">
      <v-icon>mdi-application-export</v-icon>
    </v-btn>
  </div>
</template>