diff --git a/pyomo/contrib/fbbt/fbbt.py b/pyomo/contrib/fbbt/fbbt.py
index 047e1396efa..b8a2bf20c04 100644
--- a/pyomo/contrib/fbbt/fbbt.py
+++ b/pyomo/contrib/fbbt/fbbt.py
@@ -444,7 +444,7 @@ def _prop_bnds_leaf_to_root_GeneralExpression(node, bnds_dict, feasibility_tol):
         is more conservative).
     """
     if node.expr.__class__ in native_types:
-        expr_lb = expr_up = node.expr
+        expr_lb = expr_ub = node.expr
     else:
         expr_lb, expr_ub = bnds_dict[node.expr]
     bnds_dict[node] = (expr_lb, expr_ub)
diff --git a/pyomo/contrib/fbbt/tests/test_fbbt.py b/pyomo/contrib/fbbt/tests/test_fbbt.py
index 5fafad4a992..5e8d656eeab 100644
--- a/pyomo/contrib/fbbt/tests/test_fbbt.py
+++ b/pyomo/contrib/fbbt/tests/test_fbbt.py
@@ -1317,6 +1317,20 @@ def test_external_function(self):
         self.assertAlmostEqual(m.y.lb, 0)
         self.assertAlmostEqual(m.y.ub, 3)
 
+    def test_named_expr(self):
+        m = pyo.ConcreteModel()
+        m.x = pyo.Var(bounds=(0, None))
+        m.y = pyo.Var(bounds=(1, 6))
+        m.e_const = pyo.Expression(expr=3)
+        m.e_var = pyo.Expression(expr=m.y + m.e_const)
+
+        m.c = pyo.Constraint(expr=m.x**2 == m.e_var)
+
+        self.tightener(m)
+        self.tightener(m)
+        self.assertAlmostEqual(m.x.lb, 2)
+        self.assertAlmostEqual(m.x.ub, 3)
+
 
 class TestFBBT(FbbtTestBase, unittest.TestCase):
     def setUp(self) -> None: