diff --git a/pkg/rpcclient/unwrap/unwrap.go b/pkg/rpcclient/unwrap/unwrap.go
index de82e6121..fd1d27a90 100644
--- a/pkg/rpcclient/unwrap/unwrap.go
+++ b/pkg/rpcclient/unwrap/unwrap.go
@@ -155,6 +155,9 @@ func SessionIterator(r *result.Invoke, err error) (uuid.UUID, result.Iterator, e
 	if !ok {
 		return uuid.UUID{}, result.Iterator{}, errors.New("the item is InteropInterface, but not an Iterator")
 	}
+	if (r.Session == uuid.UUID{}) && iter.ID != nil {
+		return uuid.UUID{}, result.Iterator{}, errors.New("server returned iterator ID, but no session ID")
+	}
 	return r.Session, iter, nil
 }
 
diff --git a/pkg/rpcclient/unwrap/unwrap_test.go b/pkg/rpcclient/unwrap/unwrap_test.go
index 60fc60088..2f895a07e 100644
--- a/pkg/rpcclient/unwrap/unwrap_test.go
+++ b/pkg/rpcclient/unwrap/unwrap_test.go
@@ -197,8 +197,11 @@ func TestSessionIterator(t *testing.T) {
 	require.Error(t, err)
 
 	iid := uuid.New()
-	sid := uuid.New()
 	iter := result.Iterator{ID: &iid}
+	_, _, err = SessionIterator(&result.Invoke{State: "HALT", Stack: []stackitem.Item{stackitem.NewInterop(iter)}}, nil)
+	require.Error(t, err)
+
+	sid := uuid.New()
 	rs, ri, err := SessionIterator(&result.Invoke{Session: sid, State: "HALT", Stack: []stackitem.Item{stackitem.NewInterop(iter)}}, nil)
 	require.NoError(t, err)
 	require.Equal(t, sid, rs)