So line 32 in your case studies Slice is failing
It's because it's not getting the language from the context, I guess.
If you console log the context, it's a blank object:
console.log('Context:', context);
const client = createClient();
You can't access the params inside a server component that's why the Slice is breaking, it's querying your dutch docs by their IDs in the English locale.
What can you do?
Send your params as a prop on the SliceZone component on your homepage file:
<SliceZone slices={home.data.slices} components={components} context={ params } />
And use that in the component:
return await client.getByID<Content.CasePageDocument>(
item.case_study.id,
context,
);