Misordered updates result in temporarily missing Y.Map keys about yjs HOT 5 OPEN

import * as Y from 'yjs'

const doc1 = new Y.Doc()
const doc2 = new Y.Doc()

const doc1Map = doc1.getMap('top')
const doc2Map = doc2.getMap('top')

let updates = []
doc1.on('updateV2', update => {
    updates.push(update)
})

// Set initial values on and apply updates to doc 2
doc1Map.set('x', 1)
doc1Map.set('y', 2)
Y.applyUpdateV2(doc2, updates[0])
Y.applyUpdateV2(doc2, updates[1])
updates = []
console.log(doc2Map.toJSON())   // => { x: 1, y: 2 }

// Change two values, but apply updates to doc 2 in reverse order
doc1Map.set('x', 3)
doc1Map.set('y', 4)
Y.applyUpdateV2(doc2, updates[1])
console.log(doc2Map.toJSON())   // => { x: 1 }  y is entirely missing!
console.log('pendingStruct', doc2.store.pendingStructs)
Y.applyUpdateV2(doc2, updates[0])
console.log(doc2Map.toJSON())   // => { x: 3, y: 4 }
console.log('pendingStruct', doc2.store.pendingStructs)

import { decodeUpdate, decodeUpdateV2, Doc } from 'yjs'

function willMissingUpdateImpl (
  doc: Doc,
  update: Uint8Array,
  decode: typeof decodeUpdateV2 | typeof decodeUpdate
): false | Map<number, number> {
  const { structs } = decode(update)
  // clientId -> clock
  const missingMap = new Map<number, number>()

  // find if missing update in the structs
  for (let i = 0; i < structs.length; i++) {
    const struct = structs[i]
    const client = struct.id.client
    const items = doc.store.clients.get(client) ?? []
    const lastItem = items.at(-1)
    if (!lastItem) {
      if (struct.id.clock !== 0) {
        missingMap.set(client, struct.id.clock)
      }
      continue
    }
    const nextClock = lastItem.id.clock + lastItem.length
    if (nextClock < struct.id.clock) {
      missingMap.set(client, struct.id.clock)
    }
  }
  return missingMap.size > 0 ? missingMap : false
}

export function willMissingUpdate (
  doc: Doc, update: Uint8Array): false | Map<number, number> {
  return willMissingUpdateImpl(doc, update, decodeUpdate)
}

export function willMissingUpdateV2 (
  doc: Doc, update: Uint8Array): false | Map<number, number> {
  return willMissingUpdateImpl(doc, update, decodeUpdateV2)
}