Laravel 8 upsert doesn't work as expected

I'm trying use upsert as explained here (https://stackoverflow.com/a/66200086/1240380) and in 8.x doc but it is not working as expected.

CartItem::upsert(
    [
        [
            "id" => 105,
            "unit_price" => 146.5124,
            "price" => 293.0248,
            "unit_taxes" => 28.22,
            "taxes" => 56.44,
            "custom_fields" => '{"options":{"estado":15,"user_id":1},"calculated_price":146.5124,"calculated_tax_price":28.22}'
        ],
        [
            "id" => 106,
            "unit_price" => 113.8824,
            "price" => 227.7648,
            "unit_taxes" => 11.54,
            "taxes" => 23.08,
            "custom_fields" => '{"options":{"estado":15,"user_id":1},"calculated_price":"113.8824","calculated_tax_price":"11.539999999999999"}'
        ],
    ],
    'id'
);

The code above is producing the following error

Illuminate\Database\QueryException

SQLSTATE[HY000]: General error: 1364 Field 'cart_id' doesn't have a default value (SQL: insert into cart_items (created_at, custom_fields, id, price, taxes, unit_price, unit_taxes, updated_at) values (2022-01-14 20:41:44, {"options":{"estado":15,"user_id":1},"calculated_price":146.5124,"calculated_tax_price":28.22}, 105, 293.0248, 56.44, 146.5124, 28.22, 2022-01-14 20:41:44), (2022-01-14 20:41:44, {"options":{"estado":15,"user_id":1},"calculated_price":"113.8824","calculated_tax_price":"11.539999999999999"}, 106, 227.7648, 23.08, 113.8824, 11.54, 2022-01-14 20:41:44) on duplicate key update id = values(id), unit_price = values(unit_price), price = values(price), unit_taxes = values(unit_taxes), taxes = values(taxes), custom_fields = values(custom_fields), updated_at = values(updated_at))

The id column is the PK of the table. I also tried using the third param without success.

I cannot understand why it is not working as expected. For some reason the rows exists but they are not detected. The error suggests that laravel is trying creating new rows instead of update the previous one.

Is there something missing?

The rows in question:

The table definition:

EDIT 1: About the columns types, price and unit_price are int but I tried float because in the CartItem I have they configured in $casts variable to cast them to "Money" type (saving them as cents). I tried with int values but I got the same result.