Free standard listings allow merchants to show out of stock products to users. To ensure good user experience, Google will now preemptively disapprove free standard listings for products that are marked as out of stock in the product data in Merchant Center, but are in stock on their landing pages.
Take action to prevent disapprovals
To avoid having your products be preemptively disapproved, make sure that your Merchant Center product data’s availability values accurately reflect each product’s availability on its corresponding landing page. It is recommended that you enable automatic item updates in your Merchant Center account to help reduce the likelihood of inconsistencies. Learn more about automatic item updates