diff --git a/Makefile b/Makefile
index 0ef29849bf..50229d3391 100644
--- a/Makefile
+++ b/Makefile
@@ -141,7 +141,7 @@ clean-local:
 check-merges-reproducibility:
 	@echo "Running replay_merge for each idx in parallel using GNU Parallel..."
 	@set -e; \
-	tail -n +2 $(CSV_RESULTS) | awk -F, '{print $$1}' | parallel --halt now,fail=1 -j 50% python3 src/python/replay_merge.py --merges_csv $(CSV_RESULTS) -skip_build -delete_workdir --idx {}
+	tail -n +2 $(CSV_RESULTS) | awk -F, '{print $$1}' | parallel --halt now,fail=1 -j 50% python3 src/python/replay_merge.py --testing --merges_csv $(CSV_RESULTS) -skip_build -delete_workdir --idx {}
 
 protect-repos:
 	find repos -mindepth 1 -type d -exec chmod a-w {} +