Still see the products in search results, even when all the variants are sold out and product is hidden?

Please check whether you use any app for search filters to show the products quickly.

Sometimes such app cache the products. The product shows even though it is hidden since it is being cached.

If that is the case, You can check with that app's developers to learn how to prevent caching the hidden products.

If this is not the case, please provide us with screenshots and more details.