diff --git a/utils/dataloaders.py b/utils/dataloaders.py
index fb3d065fadce..ff1873a28356 100755
--- a/utils/dataloaders.py
+++ b/utils/dataloaders.py
@@ -732,7 +732,8 @@ def load_mosaic(self, index):
             # Labels
             labels, segments = self.labels[index].copy(), self.segments[index].copy()
             if i == 3:
-                labels += labels10
+                for label in labels10:
+                    labels = np.concatenate((labels, label), 0)
             if labels.size:
                 labels[:, 1:] = xywhn2xyxy(labels[:, 1:], w, h, padw, padh)  # normalized xywh to pixel xyxy format
                 segments = [xyn2xy(x, w, h, padw, padh) for x in segments]