Frontastic has a built-in mechanism to generate and serve sitemaps for your projects. This mechanism is typically triggered on a nightly basis on all servers of a customer. When scaling up, the latest deployed server image is used to create new servers. If your latest deployment took place a long time ago, the sitemap served from this new server will be outdated.
While this issue rarely happens, we've fixed it on an architectural level.
However, how you work with sitemaps will change. Because the sitemap setup differs a lot between projects, you'll now need to manually activate the new storage mechanism in your project. To do that, you'll need to follow the steps in our Migrating sitemap storage article.
This fix also means that you can now leverage stateless controllers. To do this, follow the steps in our Truly stateless controllers article.