diff --git a/paynt/quotient/pomdp_family.py b/paynt/quotient/pomdp_family.py
index d92d08fd7..cddc66442 100644
--- a/paynt/quotient/pomdp_family.py
+++ b/paynt/quotient/pomdp_family.py
@@ -241,10 +241,11 @@ def compute_qvalues_for_fsc(self, dtmc_sketch):
         product_state_to_value = result.get_values()
 
         # map state values to the resulting map
+        product_state_to_state_memory_action = self.product_pomdp_fsc.product_state_to_state_memory_action.copy()
         state_memory_action_to_value = {}
         invalid_action = self.num_actions
         for product_state in range(product.nr_states):
-            state,memory_action = self.product_pomdp_fsc.product_state_to_state_memory_action[product_state]
+            state,memory_action = product_state_to_state_memory_action[product_state]
             memory,action = memory_action
             if action == invalid_action:
                 continue