diff --git a/cvat/apps/lambda_manager/views.py b/cvat/apps/lambda_manager/views.py
index 9edb5889ae75..d8d6b7e7b820 100644
--- a/cvat/apps/lambda_manager/views.py
+++ b/cvat/apps/lambda_manager/views.py
@@ -836,7 +836,9 @@ def parse_anno(anno, labels):
                 elif anno["type"] == "mask":
                     [xtl, ytl, xbr, ybr] = shape["points"][-4:]
                     cut_points = shape["points"][:-4]
-                    rle = mask_tools.mask_to_rle(np.array(cut_points))["counts"].tolist()
+                    rle = mask_tools.mask_to_rle(np.array(cut_points)[:, np.newaxis])[
+                        "counts"
+                    ].tolist()
                     rle.extend([xtl, ytl, xbr, ybr])
                     shape["points"] = rle