diff --git a/include/piqp/sparse/blocksparse_stage_kkt.hpp b/include/piqp/sparse/blocksparse_stage_kkt.hpp
index 611ca73..b716bab 100644
--- a/include/piqp/sparse/blocksparse_stage_kkt.hpp
+++ b/include/piqp/sparse/blocksparse_stage_kkt.hpp
@@ -669,7 +669,7 @@ class BlocksparseStageKKT : public KKTSystem<T>
                     if (!A_kkt.B[block_index - 1]) {
                         A_kkt.B[block_index - 1] = std::make_unique<BlasfeoMat>(last_block_off_diag_size, last_block_diag_size);
                     }
-                    BLASFEO_DMATEL(A_kkt.B[block_index - 1]->ref(), i - block_start, j + last_block_off_diag_size - block_start) = v;
+                    BLASFEO_DMATEL(A_kkt.B[block_index - 1]->ref(), i - block_start, j - last_block_start) = v;
                 }
             }
         }
diff --git a/tests/data/scenario_mpc.mat b/tests/data/scenario_mpc.mat
new file mode 100644
index 0000000..796b009
Binary files /dev/null and b/tests/data/scenario_mpc.mat differ
diff --git a/tests/src/sparse/blocksparse_stage_kkt_test.cpp b/tests/src/sparse/blocksparse_stage_kkt_test.cpp
index aafc856..9071cab 100644
--- a/tests/src/sparse/blocksparse_stage_kkt_test.cpp
+++ b/tests/src/sparse/blocksparse_stage_kkt_test.cpp
@@ -194,6 +194,6 @@ TEST_P(BlocksparseStageKKTTest, FactorizeSolveSQP)
 }
 
 INSTANTIATE_TEST_SUITE_P(FromFolder, BlocksparseStageKKTTest,
-                         ::testing::Values("small_sparse_dual_inf", "small_dense",
+                         ::testing::Values("small_sparse_dual_inf", "small_dense", "scenario_mpc",
                                            "chain_mass_sqp", "robot_arm_sqp",
                                            "robot_arm_sqp_constr_perm", "robot_arm_sqp_no_global"));