How to mongo aggregate with lookup and geoIntersects

Can anyone help me with this, if i run this query:
db.getCollection(‘users’).aggregate([
{ $unwind: ‘$addresses’ },
{ $project: { coordinates: [ ‘$addresses.region.longitude’, ‘$addresses.region.latitude’ ] } },
])

I get this results:

/* 1 */
{
    "_id" : ObjectId("6197a78308591026b742cbc7"),
    "coordinates" : [ 
        -8.88180350512795, 
        38.5628716186268
    ]
}

/* 2 */
{
    "_id" : ObjectId("6199798916317b0c2dcab874"),
    "coordinates" : [ 
        -9.15904389999993, 
        38.7235087
    ]
}

/* 3 */
{
    "_id" : ObjectId("6199798916317b0c2dcab874"),
    "coordinates" : [ 
        -8.6923178, 
        41.1846394
    ]
}

Then if i add a lookup with a pipeline:

db.getCollection('users').aggregate([
{ $unwind: '$addresses' },
{ $project: { coordinates: [ '$addresses.region.longitude', '$addresses.region.latitude' ] } },
{
    $lookup: {
        from: 'deliveryareas',
        let: { userCoordinates: '$coordinates' },
        pipeline: [
            { $match: {
                area: {
                    $geoIntersects: {
                        $geometry: {
                            type: 'Point',
                            coordinates: '$userCoordinates',
                        },
                    },
                }
            } },
        ],
        as: 'inRegion',
    },
},
])

I get the error: i have the error: Point must be an array or object!

But if i replace the variable $$userCoordinates by a fixed value, for example [ -8.88180350512795, 38.5628716186268 ] (that i have on the users) the query run with success.