Prerequisites

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

Mongoose version

8.5.3

Node.js version

22.5.1

MongoDB server version

5.0

Typescript version (if applicable)

4.9.5

Description

The Typescript type for populate's return value:

const result = await SomeModel.findOne().populate<{ otherInfo: string }>("other");

includes MergeType<{ [x: string]: NativeDate; } & ....

This causes later code to assume every property is of type NativeDate.

This was observed after upgrading from mongoose 6.12.0 to 8.5.3.

Steps to Reproduce

1. Create any model.
2. Call findOne, followed by populate with a type parameter.

Expected Behavior

The types to be properly merged without { [x: string]: NativeDate; } being included.