diff --git a/NodeGraphQt/base/graph.py b/NodeGraphQt/base/graph.py
index 8a0c50ee..21015e2b 100644
--- a/NodeGraphQt/base/graph.py
+++ b/NodeGraphQt/base/graph.py
@@ -1612,6 +1612,9 @@ def _deserialize(self, data, relative_pos=False, pos=None):
                 if allow_connection:
                     self._undo_stack.push(PortConnectedCmd(in_port, out_port))
 
+                # Run on_input_connected to ensure connections are fully set up after deserialization.
+                in_node.on_input_connected(in_port, out_port)
+
         node_objs = nodes.values()
         if relative_pos:
             self._viewer.move_nodes([n.view for n in node_objs])