Eloquent Model Attribute Blank Before Processing in Laravel

I'm trying to pass an attribute (cartonsData) into my InwardTransaction model, process it inside the model, and save related details in another model (CartonTransaction). However, I noticed that cartonsData is blank before it reaches my model's saving event.

My Tinker Test

$transaction = InwardTransaction::create([
    'date' => '10/03/2025',
    'type' => \App\Enums\TransactionType::INWARDS,
    'description' => 'Random',
    'cartonsData' => [
        [
            "items" => [
                ["item_id" => "1", "quantity" => "100"],
                ["item_id" => "2", "quantity" => "100"]
            ],
            "numCartons" => "1"
        ],
        [
            "items" => [
                ["item_id" => "3", "quantity" => "1000"]
            ],
            "numCartons" => "5"
        ]
    ],
]);

echo($transaction);

Issue When I log the data inside the booted() method of my model, the cartonsData attribute is empty.

protected static function booted(): void
{
    static::saving(function (self $transaction) {
        Log::info("Data Received:", $transaction->toArray());
    });
}

Log I received:

[2025-03-24 12:07:32] local.INFO: Data Received: {"date":"2025-10-03T00:00:00.000000Z","type":"inwards","description":"Random"} 

What I Need

-I want to properly retrieve the cartonsData attribute in the model.

-Process it inside the model.

-Save the details into a related model CartonTransaction (which belongs to InwardTransaction).

What Could Be Wrong?

-Is Laravel stripping out cartonsData before it reaches the model?

-Do I need a mutator (setCartonsDataAttribute) to ensure it persists?

-Is fillable or casts affecting this behavior?

Any insights would be appreciated! Thanks.