redux-toolkit: Optimistic updates not working on a graphql-based base query

I’m trying to implement optimistic updates on my graphql-based base query setup; however, after the mutation is triggered, the api.util.updateQueryData call seems not to be updating the cached data.

Here’s my endpoint:

import { createApi, retry } from '@reduxjs/toolkit/query/react';
import { gql } from 'graphql-request';
import { graphqlRequestBaseQuery } from '@rtk-query/graphql-request-base-query';

export const api = createApi({
  reducerPath: 'api',
  baseQuery: backedOffGraphqlBaseQuery,
  tagTypes: ['order', 'user', 'vehicle'],
  endpoints: (builder) => ({
    [...]
    transitionOrderStatus: builder.mutation<string, { status: OrderStatus; orderId: string }>({
      query: ({ status, orderId }) => ({
        document: gql`mutation transitionOrderStatus($status: OrderStatus!, $orderId: String!) {
    transitionOrderStatus(status: $status, orderId: $orderId)
  }`,
        variables: {
          status,
          orderId,
        },
      }),
      async onQueryStarted({ orderId }, { dispatch, queryFulfilled }) {
        const patchResult = dispatch(
          api.util.updateQueryData('getOpenOrders', orderId, (ordersDraft) => {
            const orders = ordersDraft.filter((o) => o.id !== orderId);
            ordersDraft = orders;
          }),
        );

        try {
          await queryFulfilled;
        } catch (error) {
          patchResult.undo();
        }
      },
      // invalidatesTags: ['order'],
    }),
    [...]

Any thoughts on why the dispatched api.util.updateQueryData action is not getting the cached data updated?

Thanks! By the way, I’m almost done migrating our production web app to RTK Query and I’m fascinated by it. Also, I’ve found the docs extremely educative and just FUN!