diff --git a/src/backend/langflow/graph/graph/base.py b/src/backend/langflow/graph/graph/base.py
index 1c1aa923b..453076e1b 100644
--- a/src/backend/langflow/graph/graph/base.py
+++ b/src/backend/langflow/graph/graph/base.py
@@ -631,7 +631,7 @@ class Graph:
         vertices: List[Vertex],
     ) -> List[List[str]]:
         """Performs a layered topological sort of the vertices in the graph."""
-        vertices_ids = [vertex.id for vertex in vertices]
+        vertices_ids = {vertex.id for vertex in vertices}
         # Queue for vertices with no incoming edges
         queue = deque(
             vertex.id for vertex in vertices if self.in_degree_map[vertex.id] == 0
@@ -646,7 +646,10 @@ class Graph:
                 vertex_id = queue.popleft()
                 layers[current_layer].append(vertex_id)
                 for neighbor in self.successor_map[vertex_id]:
-                    # only vertices in `vertices` are considered
+                    # only vertices in `vertices_ids` should be considered
+                    # because vertices by have been filtered out
+                    # in a previous step. All dependencies of theirs
+                    # will be built automatically if required
                     if neighbor not in vertices_ids:
                         continue