diff --git a/cpp/include/raft/neighbors/detail/ivf_flat_interleaved_scan-inl.cuh b/cpp/include/raft/neighbors/detail/ivf_flat_interleaved_scan-inl.cuh
index 18f1906dc5..81779668c4 100644
--- a/cpp/include/raft/neighbors/detail/ivf_flat_interleaved_scan-inl.cuh
+++ b/cpp/include/raft/neighbors/detail/ivf_flat_interleaved_scan-inl.cuh
@@ -884,6 +884,7 @@ void launch_kernel(Lambda lambda,
     queries += grid_dim_y * index.dim();
     neighbors += grid_dim_y * grid_dim_x * k;
     distances += grid_dim_y * grid_dim_x * k;
+    coarse_index += grid_dim_y * n_probes;
   }
 }
 
diff --git a/cpp/test/neighbors/ann_ivf_flat.cuh b/cpp/test/neighbors/ann_ivf_flat.cuh
index d72d73680a..71d48cdeb7 100644
--- a/cpp/test/neighbors/ann_ivf_flat.cuh
+++ b/cpp/test/neighbors/ann_ivf_flat.cuh
@@ -497,6 +497,11 @@ const std::vector<AnnIvfFlatInputs<int64_t>> inputs = {
    raft::matrix::detail::select::warpsort::kMaxCapacity * 4,
    raft::matrix::detail::select::warpsort::kMaxCapacity * 4,
    raft::distance::DistanceType::InnerProduct,
-   false}};
+   false},
+
+  // The following two test cases should show very similar recall.
+  // num_queries, num_db_vecs, dim, k, nprobe, nlist, metric, adaptive_centers
+  {20000, 8712, 3, 10, 51, 66, raft::distance::DistanceType::L2Expanded, false},
+  {100000, 8712, 3, 10, 51, 66, raft::distance::DistanceType::L2Expanded, false}};
 
 }  // namespace raft::neighbors::ivf_flat