Filament Form: Dynamic additional_fields values not being saved properly

// In ProductResource
Section::make('Ek Bilgi Alanları')
    ->schema(fn(Get $get): array => self::getAdditionalFields($get('product_group_ids')))
    ->columns(2)
    ->statePath('additional_fields')
    ->dehydrated(true) 

// getAdditionalFields method
protected static function getAdditionalFields(?array $productGroupIds): array
{
    // ... get fields 
    
    return $additionalFields->map(function ($field) {
        $fieldKey = Str::snake($field->value ?: $field->field_name);
        
        $component = match ($field->field_type) {
            'free-text' => TextInput::make("additional_fields.{$fieldKey}")
                ->label($field->value ?: $field->field_name)
                ->default(''),

        };
        
        return $component;
    })->toArray();
Product Model
    public function setAdditionalFieldsAttribute($value)
    {
        $this->attributes['additional_fields'] = is_array($value) ? json_encode($value) : $value;
    }
    public function getAdditionalFieldsAttribute($value)
    {
        return json_decode($value, true) ?? [];
    }
}