Why update() called in directive, when changing not-related refs?

[modelair]

hello.
Why update() called in directive, when changing not-related refs?
by the way, documentation says "update called after the parent component and all of its children have updated"

vue 3.3.4

repro:

main.ts

import { createApp } from 'vue'
import App from './App.vue'

const app = createApp(App)

const directive = {
    updated() {
        console.log('updated')
    }
}
app.directive('test', directive)
app.mount('#app')

app.ts

<script setup lang="ts">
import { ref } from 'vue'

const inputModel = ref()
</script>

<template>
   <div>
    <button v-test>v-test</button>
  </div>
  <div>
    <input v-model="inputModel">
    <button @click="inputModel = 123">update ref</button>
  </div>
</template>