Error in $doc.update()?

foundry.js:13637 Uncaught (in promise) Error: You must provide an _id for every object in the update data Array.
    at #preUpdateDocumentArray (foundry.js:13637:32)
    at ClientDatabaseBackend._updateDocuments (foundry.js:13449:73)
    at ClientDatabaseBackend.update (commons.js:8677:19)
    at async Actor5e.updateDocuments (commons.js:8001:23)
    at async Actor5e.update (commons.js:8098:23)

<script>
  import { log, update } from "~/src/helpers/Utility";
  import { Timing } from "@typhonjs-fvtt/runtime/util";
  import { createEventDispatcher, getContext, onDestroy, onMount  } from "svelte";
  
  export let document = false;
  
  const dispatch = createEventDispatcher();
  const doc = document || getContext("#doc");
  const updateDebounce = (path) => Timing.debounce($doc.update({[path]: event.target.value }), 300);

  $: systemAbilities = game.system.config.abilities
  $: systemAbilitiesArray = Object.entries(systemAbilities);

</script>

<template lang="pug">
.attribute-entry.mt-sm
  +each("systemAbilitiesArray as ability, index")
    .flexrow.mb-sm
      .flex1 {ability[1].label}
      .flex3.right
        input(type="number" value="{$doc.system.abilities[ability[1].abbreviation].value}" on:input="{updateDebounce(`system.abilities.${ability[1].abbreviation}.value`)}" style="width: 40px")

</template>