diff --git a/tutorials/decoupled_mobo.ipynb b/tutorials/decoupled_mobo.ipynb
index 2a969e7df4..855f70974d 100644
--- a/tutorials/decoupled_mobo.ipynb
+++ b/tutorials/decoupled_mobo.ipynb
@@ -787,9 +787,9 @@
         "log_hv_difference_rnd = np.log10(problem.max_hv - np.asarray(hvs_random))\n",
         "\n",
         "fig, ax = plt.subplots(1, 1, figsize=(8, 6))\n",
-        "running_cost_random = np.cumsum(cost_random.cpu()[N_INIT-1:])\n",
-        "running_cost_qnehvi = np.cumsum(cost_qnehvi.cpu()[N_INIT-1:])\n",
-        "running_cost_hvkg = np.cumsum(cost_hvkg.cpu()[N_INIT-1:])\n",
+        "running_cost_random = np.cumsum(cost_random.cpu().numpy()[N_INIT-1:])\n",
+        "running_cost_qnehvi = np.cumsum(cost_qnehvi.cpu().numpy()[N_INIT-1:])\n",
+        "running_cost_hvkg = np.cumsum(cost_hvkg.cpu().numpy()[N_INIT-1:])\n",
         "ax.errorbar(\n",
         "    running_cost_random,\n",
         "    log_hv_difference_rnd[: len(running_cost_random)],\n",