$lookup with "pipeline" keyword - no result

db.customers.aggregate([
    {"$match": {"_id": "CUSTOMER-8165f7af-69b4-402d-ae68-b72b86682fb9"}},
    {
        "$lookup": {
            "from": "licenses",
            "let": {"customerId": "$_id"},
            "pipeline": [
                {"$match": {"customerId": "$$customerId"}},
                {"$sort": {"createdAt": 1}},
            ],
            "as": "licenses",
        }
    },
]);