diff --git a/xugrid/ugrid/ugrid2d.py b/xugrid/ugrid/ugrid2d.py
index bf2b586a..820db066 100644
--- a/xugrid/ugrid/ugrid2d.py
+++ b/xugrid/ugrid/ugrid2d.py
@@ -2264,7 +2264,7 @@ def from_structured_bounds(
                     f"Your structured bounds contain {len(keep) - keep.sum()} invalid faces.\n"
                     "These will be omitted from the Ugrid2d topology.",
                 )
-                index = index[keep]
+                index &= keep
                 face_node_connectivity[~valid] = -1
                 face_node_connectivity = connectivity.renumber(
                     face_node_connectivity[keep]