Vue.js vuetify v-textarea not auto growing correctly inside v-layout that's un expanded

I have had a similar problem, and solved it by setting the key attribute of the v-textarea to a variable and changing said variable manually, forcing the component to re-render. After the re-render, auto-grow worked correctly.

<template>
  <v-textarea
    :key="autoGrowHack"
    v-model="textAreaVal"
    auto-grow
  ></v-textarea>
</template>

<script>
export default {
  data() {
    return {
      autoGrowHack: false,
      textAreaVal: "lorem ipsum",
    }
  },
  methods: {
    forceReRender() {
      this.autoGrowHack = !this.autoGrowHack;
    }
  },
}
</script>

As far as when to call the forceReRender function, that's going to depend on specifics in your code. I was using this v-textarea inside a component on a v-stepper tab, and found that triggering the switch when the v-stepper's step is changed to the one with this component on it made it work.

I'm guessing this is related to the following open bug on vuetify that also relates to auto-grow: https://github.com/vuetifyjs/vuetify/issues/6995