diff --git a/infra/build/functions/request_build.py b/infra/build/functions/request_build.py
index b7046c7eb..f636397e5 100644
--- a/infra/build/functions/request_build.py
+++ b/infra/build/functions/request_build.py
@@ -32,7 +32,7 @@ MAX_BUILD_HISTORY_LENGTH = 64
 
 def update_build_history(project_name, build_id, build_tag):
   """Update build history of project."""
-  project_key = ndb.Key(BuildsHistory, project_name + build_tag)
+  project_key = ndb.Key(BuildsHistory, project_name + '-' + build_tag)
   project = project_key.get()
 
   if not project:
diff --git a/infra/build/functions/request_build_test.py b/infra/build/functions/request_build_test.py
index 9589c09b4..d73467216 100644
--- a/infra/build/functions/request_build_test.py
+++ b/infra/build/functions/request_build_test.py
@@ -82,7 +82,7 @@ class TestRequestBuilds(unittest.TestCase):
                     build_tag='fuzzing',
                     project='test-project',
                     build_ids=[str(i) for i in range(1, 65)]).put()
-      update_build_history('test-project', '65', '-fuzzing')
+      update_build_history('test-project', '65', 'fuzzing')
       expected_build_ids = [str(i) for i in range(2, 66)]
 
       self.assertEqual(BuildsHistory.query().get().build_ids,