diff --git a/src/triangle/_impl/_tri_delaunay_impl.scad b/src/triangle/_impl/_tri_delaunay_impl.scad
index 45d9aa24..d8a8b319 100644
--- a/src/triangle/_impl/_tri_delaunay_impl.scad
+++ b/src/triangle/_impl/_tri_delaunay_impl.scad
@@ -130,7 +130,7 @@ function _adjustNeighborsDtri(d, newTriangles, leng, _indices_hash, i = 0) =
 					let(
 						neighbors = hashmap_get(delaunay_triangles(d), delaunayTri, hash = _indices_hash),
 						leng_nbrs = len(neighbors),
-						nbri = find_index(neighbors, function(nbr) nbr != undef && contains(nbr, edge[1]) && contains(nbr, edge[0])),
+						nbri = find_index(neighbors, function(nbr) contains(nbr, edge[1]) && contains(nbr, edge[0])),
 						nd = nbri == -1 ? d : updateNbrs(d, delaunayTri, [
 							for(j = 0; j < leng_nbrs; j = j + 1)
 								j == nbri ? newTriangles[i][0] : neighbors[j]