diff --git a/paynt/quotient/mdp_family.py b/paynt/quotient/mdp_family.py
index 9b7404a25..a652d503d 100644
--- a/paynt/quotient/mdp_family.py
+++ b/paynt/quotient/mdp_family.py
@@ -243,7 +243,7 @@ def assert_mdp_is_deterministic(self, mdp, family):
         
 
     def build_game_abstraction_solver(self, prop):
-        target_label = str(prop.formula.subformula.subformula)
+        target_label = prop.get_target_label()
         solver = stormpy.synthesis.GameAbstractionSolver(
             self.quotient_mdp, len(self.action_labels), self.choice_to_action, target_label
         )