diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index bffa87e01..d6635599f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,10 +11,10 @@ on:
         required: true
 
 env:
-  up_tamer_commit: "631dfd43a56e7c2dda44fe273ec6f5492e99cfe1"
+  up_tamer_commit: "fba59b93ed7a85370f4bbf0dc5310bbeffce05b7"
   up_pyperplan_commit: "a24854213caf5038e1540e31613d24b93825fbb3"
   up_fast_downward_commit: "c60b6ab82cb8c3046cfd4782afe4d4c6071c4109"
-  up_enhsp_commit: "78cc3331beb1fcc36380a8f698f49b4312dc411a"
+  up_enhsp_commit: "f689d3b65bed921bed35c61b468ca771ae6f54a2"
   up_fmap_commit: "f29e66c8483abcb8f17ff1c46a0745ee9b1e95fa"
 
 jobs:
diff --git a/unified_planning/engines/plan_validator.py b/unified_planning/engines/plan_validator.py
index fb35c6595..b24f78e72 100644
--- a/unified_planning/engines/plan_validator.py
+++ b/unified_planning/engines/plan_validator.py
@@ -311,6 +311,7 @@ def _apply_effect(
         updates: Dict[FNode, FNode],
         problem: Problem,
     ) -> Dict[FNode, FNode]:
+        em = problem.environment.expression_manager
         result = {}
         for instantiated_effect in effect.expand_effect(problem):
             if self._check_condition(
@@ -326,9 +327,13 @@ def _apply_effect(
                 if instantiated_effect.kind == EffectKind.ASSIGN:
                     result[g_fluent] = se.evaluate(g_value, state=state)
                 elif instantiated_effect.kind == EffectKind.DECREASE:
-                    result[g_fluent] = f_value - se.evaluate(g_value, state=state)
+                    result[g_fluent] = se.evaluate(
+                        em.Minus(f_value, g_value), state=state
+                    )
                 elif instantiated_effect.kind == EffectKind.INCREASE:
-                    result[g_fluent] = f_value - se.evaluate(g_value, state=state)
+                    result[g_fluent] = se.evaluate(
+                        em.Plus(f_value, g_value), state=state
+                    )
         return result
 
     def _states_in_interval(
diff --git a/unified_planning/test/examples/minimals.py b/unified_planning/test/examples/minimals.py
index 08d3cd194..2b224e620 100644
--- a/unified_planning/test/examples/minimals.py
+++ b/unified_planning/test/examples/minimals.py
@@ -427,6 +427,31 @@ def get_example_problems():
     counter_to_50 = TestCase(problem=problem, solvable=True, valid_plans=[plan])
     problems["counter_to_50"] = counter_to_50
 
+    # temporal counter
+    counter_f = Fluent("counter", IntType(0, 100))
+    d_increase = DurativeAction("increase")
+    d_increase.set_fixed_duration(1)
+    d_increase.add_condition(StartTiming(), LT(counter_f, 99))
+    d_increase.add_increase_effect(EndTiming(), counter_f, 2)
+    d_decrease = DurativeAction("decrease")
+    d_decrease.set_fixed_duration(1)
+    d_decrease.add_condition(StartTiming(), GT(counter_f, 0))
+    d_decrease.add_decrease_effect(EndTiming(), counter_f, 1)
+    problem = Problem("temporal_counter")
+    problem.add_fluent(counter_f)
+    problem.add_action(d_increase)
+    problem.add_action(d_decrease)
+    problem.set_initial_value(counter_f, 0)
+    problem.add_goal(Equals(counter_f, 1))
+    ttplan = up.plans.TimeTriggeredPlan(
+        [
+            (Fraction(0, 1), up.plans.ActionInstance(d_increase), Fraction(1, 1)),
+            (Fraction(2, 1), up.plans.ActionInstance(d_decrease), Fraction(1, 1)),
+        ]
+    )
+    t_counter = TestCase(problem=problem, solvable=True, valid_plans=[ttplan])
+    problems["temporal_counter"] = t_counter
+
     # basic with object constant
     Location = UserType("Location")
     is_at = Fluent("is_at", BoolType(), loc=Location)
diff --git a/unified_planning/test/test_problem.py b/unified_planning/test/test_problem.py
index 75b02a6c1..687ae4bd8 100644
--- a/unified_planning/test/test_problem.py
+++ b/unified_planning/test/test_problem.py
@@ -520,6 +520,7 @@ def test_simple_numeric_planning_kind(self):
         self.assertFalse(problem.kind.has_simple_numeric_planning())
 
         names_of_SNP_problems = [
+            "temporal_counter",
             "counter_to_50",
             "robot_decrease",
             "robot_locations_connected",