Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

8.4.0

Node.js version

22.0.0

MongoDB server version

7.3.2

Typescript version (if applicable)

No response

Description

Using running mongo queries/commands in Promise.all wrapped in a transaction throws the following error:

TypeError: Cannot pin multiple connections to the same session

I tested this using an atlas serverless database. Is it not allowed to run queries in parallel when using a transaction?

Steps to Reproduce

import mongoose from 'mongoose';
mongoose.connect(process.env.MONGO_URI || 'mongodb://localhost/transaction-test');

const userSchema = new mongoose.Schema({
  name: String,
});

const User = mongoose.model('User', userSchema);

test('user transaction test', async () => {
  await Instance.db.transaction(async session => {
    return Promise.all([
      User.findOne({}, null, { session }),
      User.findOne({}, null, { session }),
    ]);
  });
});

Expected Behavior

No error.