To fix the duplicate URL issue in your Shopify Wookie theme and lock product URLs from changing, follow these steps:
Go to your Shopify admin, click Online Store > Themes, and select Edit Code for your Wookie theme. Look for the product.liquid file or wherever your product URLs are generated. Ensure the URLs use the handle property instead of dynamic links. Also, in Settings, disable any options that automatically update URLs. Lastly, set up 301 redirects for any duplicate URLs and use canonical tags to guide search engines to the correct URL. This will keep your product URLs stable and SEO-friendly.