diff --git a/traincheck/invariant/contain_relation.py b/traincheck/invariant/contain_relation.py
index 31e90a95..ad17732b 100644
--- a/traincheck/invariant/contain_relation.py
+++ b/traincheck/invariant/contain_relation.py
@@ -1038,7 +1038,7 @@ def static_check_all(
             var_unchanged_check_passed = True
             found_expected_child_event = False
 
-            if check_relation_first:
+            if not check_relation_first:
                 # precondition check
                 if not preconditions.verify(
                     [parent_pre_record], PARENT_GROUP_NAME, trace