This is maybe a bug report about this behavior: https://nextjs-forum.com/post/1144282281796714517#message-1145336998861742150

Let me conclude it:
I have the following component as page, located at app dir -> anotherpage -> [[...page]] -> page.js:

export const revalidate = 120;

export const getPageData = cache(async () => {
    console.log("getPageDataFetchCalled")
    // const {data} = await API.graphql({query: listTodos});
    return {data: false};
})

export default async function Page({params}) {
    const data = await getPageData();

    return (
        <>
            <h1>Hello World!</h1>
            <p>{params.page[0]}</p>
        </>
    )
}

Now the weird thing: you can see, that I call const data = await getPageData(); inside of the component. The component is a server component by default, but the console.log message inside the function is called twice. Maybe the whole component is rendered twice and because of that also the function is called twice.

The double call is only in production and only on revalidation.

But why and how can I prevent this?