Cache not updated after adding paginated data through updateResult with ferry

Question

I have a paginated list of photos (by groups of 50) that I fetch via a graphql query through ferry:

query Photos(
  $paging: CursorPaging!
) {
  photos(paging: $paging) {
    edges {
      cursor
      node {
        id
        name
      }
    }
    pageInfo {
      startCursor
      endCursor
      hasNextPage
    }
    totalCount
  }
}

I've set a requestID such as 'AllMyPhotos' not dependant on the cursor and have checked that that requestID is used everywhere.

When I want to load more data, I use the updateResult function:

fetchMore: (_) {
        if (data == null) return;
        final endCursor = data!.photos.pageInfo.endCursor?.value;
        if (endCursor == null) return;
        final client = locator<Client>();
        final request = ref.read(photosReqProvider);
        client.requestController.add(request.rebuild((req) {
          print('reqID in fetchMore: ${req.requestId}');
          req.vars.paging.after.value = endCursor;
          req.updateResult = combinePhotos;
        }));
      },

GPhotosData? combinePhotos(GPhotosData? prev, GPhotosData? next) {
  if (prev == null) return next;
  return next?.rebuild((data) {
    data.photos.edges.insertAll(0, prev.photos.edges);
  });
}

I manage to get all the data in data.photos correctly.

But when I want to read the cache I only have the first 50 items inside and not all the items I have loaded so far.

final cache = locator<Client>().cache;
final photosData = cache.readQuery(photosReq);

if (photosData == null) return;

final photoIDs = photosData.projectPhotos.edges.map((edge) => edge.node.id).toList();

// photosIDs is always 50, even when the data previously contained 100,150, etc when fetchingMore

Does updateResult not update the cache for that requestID ?