Cusotm Category Select Attribute value not saving

I have created a custom category select attribute to list active categories, after choosing a category from the list and saving there is an error message displayed “attribute value is empty. Set the attribute and try again” I have checked the values of the selected category it seems like good

Category_form.xml

<?xml version="1.0" ?>
<form xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Ui:etc/ui_configuration.xsd">
    <fieldset name="general">
        <field name="category_category_attribute" formElement="select" sortOrder="20">
            <argument name="data" xsi:type="array">
                <item name="options" xsi:type="object">xxxxCustomCategoryAttributeModelConfigSourceCustomOptionList</item>
            </argument>
            <settings>
                <dataType>text</dataType>
                <label translate="true">Category</label>
                <dataScope>category</dataScope>
            </settings>
        </field>
    </fieldset>
</form>

Patch file

<?php

namespace xxxxCustomCategoryAttributeSetupPatchData;

use MagentoEavModelEntityAttributeScopedAttributeInterface;
use MagentoFrameworkSetupModuleDataSetupInterface;
use MagentoFrameworkSetupPatchDataPatchInterface;
use MagentoEavSetupEavSetup;
use MagentoEavSetupEavSetupFactory;
use MagentoCatalogModelCategory;


class CategoryAttribute implements DataPatchInterface
{

    protected $_moduleDataSetup;
    protected $_eavSetupFactory;

    public function __construct(
        ModuleDataSetupInterface $moduleDataSetup,
        EavSetupFactory $eavSetupFactory
    ) {
        $this->_moduleDataSetup = $moduleDataSetup;
        $this->_eavSetupFactory = $eavSetupFactory;
    }

    public function apply()
    {
        /** @var EavSetup $eavSetup */
        $eavSetup = $this->_eavSetupFactory->create(['setup' => $this->_moduleDataSetup]);

        $eavSetup->addAttribute(Category::ENTITY, 'category_category_attribute', [
            'type' => 'int',
            'label' => 'category list',
            'input' => 'select',
            'default' => '',
            'source' => 'xxxxCustomCategoryAttributeModelConfigSourceCustomOptionList',
            'sort_order' => 3,
            'global' => MagentoEavModelEntityAttributeScopedAttributeInterface::SCOPE_STORE,
            'group' => 'General Information',
            'visible_on_front' => true
        ]);
    }

    public static function getDependencies()
    {
        return [];
    }

    public function getAliases()
    {
        return [];
    }
}