Error on /slack/oauth_redirect using ExpressReceiver (bolt-js v3.9)

Description

Hi, I’m getting this error when my app redirects to slack/oauth_redirect. I’ve looked at #1335 but I can’t tell if its the same problem. The URLs are all https ones. I recently started using expressReceiver in order to be able to accept post requests from an external source. However, I may be using it incorrectly and thinking all wrong. Any help would be appreciated. Thank you.

[ERROR]  OAuth:InstallProvider:0 Error: The state parameter is not for this browser session.
    at new InvalidStateError (/Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/@slack/oauth/dist/errors.js:65:47)
    at InstallProvider.<anonymous> (/Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/@slack/oauth/dist/install-provider.js:498:39)
    at step (/Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/@slack/oauth/dist/install-provider.js:44:23)
    at Object.next (/Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/@slack/oauth/dist/install-provider.js:25:53)
    at /Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/@slack/oauth/dist/install-provider.js:19:71
    at new Promise (<anonymous>)
    at __awaiter (/Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/@slack/oauth/dist/install-provider.js:15:12)
    at InstallProvider.handleCallback (/Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/@slack/oauth/dist/install-provider.js:462:16)
    at /Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/@slack/bolt/dist/receivers/ExpressReceiver.js:166:42
    at Layer.handle [as handle_request] (/Users/shakauser/Desktop/shaka-slack-bot/slack-app/node_modules/express/lib/router/layer.js:95:5) {
  code: 'slack_oauth_invalid_state'

const receiver = new ExpressReceiver({ 
  token: process.env.SLACK_BOT_TOKEN,
  appToken: process.env.SLACK_APP_TOKEN,
  port: process.env.PORT || 3030,
  signingSecret: process.env.SLACK_SIGNING_SECRET,
  clientId: process.env.SLACK_CLIENT_ID,
  clientSecret: process.env.SLACK_CLIENT_SECRET,
  stateSecret: 'some-shaka-state-secret',
  scopes: scopes,
  installationStore: {
    storeInstallation: async (installation) => {
      // change the line below so it saves to your database
      if (installation.isEnterpriseInstall && installation.enterprise !== undefined) {
        // support for org wide app installation
        return await database.set(installation.enterprise.id, installation);
      }
      if (installation.team !== undefined) {
        // single team app installation
        return await database.set(installation.team.id, installation);
      }
      throw new Error('Failed saving installation data to installationStore');
    },
    fetchInstallation: async (installQuery) => {
      // change the line below so it fetches from your database
      if (installQuery.isEnterpriseInstall && installQuery.enterpriseId !== undefined) {
        // org wide app installation lookup
        return await database.get(installQuery.enterpriseId);
      }
      if (installQuery.teamId !== undefined) {
        // single team app installation lookup
        return await database.get(installQuery.teamId);
      }
      throw new Error('Failed fetching installation');
    },
    deleteInstallation: async (installQuery) => {
      // change the line below so it deletes from your database
      if (installQuery.isEnterpriseInstall && installQuery.enterpriseId !== undefined) {
        // org wide app installation deletion
        return await database.delete(installQuery.enterpriseId);
      }
      if (installQuery.teamId !== undefined) {
        // single team app installation deletion
        return await database.delete(installQuery.teamId);
      }
      throw new Error('Failed to delete installation');
    },
  },
  installerOptions: {
    // If this is true, /slack/install redirects installers to the Slack authorize URL
    // without rendering the web page with "Add to Slack" button.
    // This flag is available in @slack/bolt v3.7 or higher
    directInstall: true,
  }
});

receiver.router.use(express.json());
receiver.router.use(cors());

const app = new App({
  receiver,
  logLevel: LogLevel.DEBUG,
});

receiver.router.get('/', (req, res) => {
  res.writeHead(200);
  res.end('Home Page!');
});

receiver.router.post('/shaka-events', (req, res) => {
  res.json(req.body); 
  console.log(req.body);
});

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• bug
• enhancement (feature request)
• question
• documentation related
• example code related
• testing related
• discussion

Requirements (place an x in each of the [ ])

• I’ve read and understood the Contributing guidelines and have done my best effort to follow them.
• I’ve read and agree to the Code of Conduct.
• I’ve searched for any related issues and avoided creating a duplicate issue.