diff --git a/SUPer/interface.py b/SUPer/interface.py
index 66d522b..18948ac 100644
--- a/SUPer/interface.py
+++ b/SUPer/interface.py
@@ -141,6 +141,7 @@ def decode_duration_base(cwdo, container_area) -> float:
                 # Objects could still not fit in buffer at this point, but there's so much we can do to help authorers...
             if layout_modifier == 'N' and is_bad_split and not may_not_fit_buffer:
                 cwd = (base_box_wd,)
+                cbox = base_box
                 scores[0] = score_container
                 layout_modifier = 'S'