Hi,
As mentioned in #2634, creating a mutator for the array type attribute will throw an error while setting the value to the attribute. This error will be thrown because of the invalid value prepared for the update action. So I override normalizeCastClassResponse method from Illuminate\Database\Eloquent\Concerns\HasAttributes trait and force it to add the key name all the time.

So if we have something like this on our model class

protected function skills(): Attribute
{
 return Attribute::make(
 get: fn ($value) => $value,
 set: fn ($values) => array_unique($values)
 );
}

we do not get an error anymore.