This is expected behaviour, you're switching locale by navigating to a (technically different) page so page setup is called again. If you don't want this to happen you can move data fetching outside of the page, in something like a store or layout for example.

@BobbieGoede
Is this still the case?
Because if I use useAsyncData() without a key let's say:
const { data } = await useAsyncData(() =>
getSomeData()
.then((response) => response.data)
.catch(() => {}),
);

Then after switching locale, this won't re-execute.