Error combining APQ (Automatic Persisted Queries) with Batch Querying in Apollo Angular

[anyplin]

Description:

I'm encountering an error when trying to use Automatic Persisted Queries (APQ) together with batch querying in Apollo Angular. The documentation Automatic Persisted Queries (Apollo Angular) -> section More suggests this combination is possible, but I'm receiving the following error:

{
  "errors": [
    {
      "message": "Error in session [sessionID]: query can't be null",
      "extensions": {
        "session": "[sessionID]",
        "statusCode": 500
      }
    }
  ]
}

Observations:

• The browser console shows the queries are batched and sent as an APQ.

[
  {
    "operationName": "[query1]",
    "variables": {},
    "extensions": {
      "persistedQuery": {
        "version": 1,
        "sha256Hash": "[hashForQuery1]"
      }
    }
  },
  {
    "operationName": "[query2]",
    "variables": {},
    "extensions": {
      "persistedQuery": {
        "version": 1,
        "sha256Hash": "[hashForQuery2]"
      }
    }
  }
]

• Using APQ or batch querying individually works as expected.
• The issue occurs only when both features are combined.

Steps Taken:

I followed the APQ documentation and concatenated createPersistedQueryLink({sha256}) before the batch link in the APOLLO_OPTIONS provider.

import { ApolloLink, Operation } from '@apollo/client/core';
import { NetworkError } from '@apollo/client/errors';
import { APOLLO_OPTIONS } from 'apollo-angular';
import { HttpBatchLink } from 'apollo-angular/http';
import { createPersistedQueryLink } from 'apollo-angular/persisted-queries';
import { sha256 } from 'crypto-hash';
import { GraphQLError } from 'graphql';

 
@NgModule({
  imports: [ApolloModule],
  providers: [
    {
      provide: APOLLO_OPTIONS,
      useFactory(httpLink: HttpBatchLink) {
        const errorLink: ApolloLink = onError(({ graphQLErrors, networkError }: {
      operation: Operation, graphQLErrors?: readonly GraphQLError[], networkError?: NetworkError;
    }) => {
      if (graphQLErrors) {
        graphQLErrors.map((graphQLError: GraphQLError) => {
          console.error(graphQLError);
        })
      }
      if (networkError) {
        console.error(networkError);
      }
    });
        const automaticPersistedQueryLink: ApolloLink = createPersistedQueryLink({ sha256 });
        return {
          // other options e.g. cache ...
          link: errorLink.concat(automaticPersistedQueryLink).concat(httpLink.create({ uri: '[GRAPHQL LINK]' })),
        };
      },
      deps: [HttpBatchLink],
    },
  ],
})
class AppModule {}

Request:

Does anyone have an example demonstrating successful use of APQ with batch querying (as suggested in the documentation)?
Alternatively, any suggestions on how to resolve the "query can't be null" error would be appreciated.
Thank you!

Note:

I've replaced sensitive information with bracketed placeholders like [sessionID], [query1], [hashForQuery1], [query2], [hashForQuery2], and [GRAPHQL LINK].

[anyplin]

It appears to be a server-side error, so I will be closing this discussion.