$Geonear does not work in the aggregation pipeline - node.js

Question

I've got a tour collection with the following model:
const tourSchema = new mongoose.Schema(
{
slug: {
type: String,
},
name: {
type: String,
required: ['true', 'a tour must have a name'],
unique: true,
trim: true,
maxlength: [40, 'a tour name must not be more than 40 characters'],
minlength: [10, 'a tour must not be less than 10 characters'],
// validate: [validator.isAlpha, 'name should only contain A-Z'],
},
duration: {
type: Number,
required: [true, 'a tour must have a duration'],
},
maxGroupSize: {
type: Number,
required: [true, 'a tour must have a group size'],
},
difficulty: {
type: String,
required: [true, 'a tour should have a difficulty'],
enum: {
values: ['easy', 'medium', 'difficult'],
message: 'Difficulty is either easy, medium or difficult',
},
},
ratingsAverage: {
type: Number,
default: 4.5,
min: [1, 'Rating must be more than 1'],
max: [5, 'Maximum rating is 5'],
set: (val) => Math.round(val * 10) / 10,
},
ratingsQuantity: {
type: Number,
default: 0,
},
price: {
type: Number,
required: ['true', 'a tour must have a price'],
},
priceDiscount: {
type: Number,
validate: {
validator: function (val) {
// this only points to current doc on NEW document creation
return val < this.price;
},
message: 'Discount price {VALUE} should be lower than regualr price',
},
},
summary: {
type: String,
trim: true,
required: ['true', 'a tour must have a description'],
},
description: {
type: String,
trim: true,
},
imageCover: {
type: String,
required: ['true, a tour must have a cover image'],
},
images: [String],
createdAt: {
type: Date,
default: Date.now(),
select: false,
},
startDates: [Date],
secretTour: {
type: Boolean,
default: false,
},
startLocation: {
// GEOJSON
type: {
type: String,
default: 'Point',
enum: ['Point'],
},
coordinates: [Number],
address: String,
description: String,
},
locations: [
{
type: {
type: String,
default: 'Point',
enum: ['Point'],
},
coordinates: [Number],
address: String,
description: String,
day: Number,
},
],
guides: [{ type: mongoose.Schema.ObjectId, ref: 'User' }],
},
{
toJSON: { virtuals: true },
toObject: { virtuals: true },
}
);
I've written an aggregate of type $GeoNear like this:
const distances = await Tour.aggregate([
{
$geoNear: {
near: {
type: 'Point',
coordinates: [lng * 1, lat * 1],
},
distanceField: 'distance',
distanceMultiplier: multiplier,
},
},
]);
I've read the official documentation, and everything else that I could find online, left no stone upturned.
I'm aware that I should have a '2dSphere' index. And it exists on my mongoDB. I've also made sure that this is the first aggregation in the pipeline.
However the results are always empty! this is so frustrating! could be because of this https://github.com/parse-community/parse-server/pull/6540. Any opinion is much appreciated.