diff --git a/src/interp/iz3proof_itp.cpp b/src/interp/iz3proof_itp.cpp
index e89aa1d6d..52ddcd64f 100755
--- a/src/interp/iz3proof_itp.cpp
+++ b/src/interp/iz3proof_itp.cpp
@@ -3078,6 +3078,11 @@ public:
     m().dec_ref(add_pos);
     m().dec_ref(rewrite_A);
     m().dec_ref(rewrite_B);
+    m().dec_ref(normal_step);
+    m().dec_ref(normal_chain);
+    m().dec_ref(normal);
+    m().dec_ref(sforall);
+    m().dec_ref(sexists);
   }
 };