diff --git a/zuul/configloader.py b/zuul/configloader.py
index c0ea9cf..eb5a0aa 100644
--- a/zuul/configloader.py
+++ b/zuul/configloader.py
@@ -1492,7 +1492,9 @@
         if trusted:
             branches = ['master']
         else:
-            branches = project.source.getProjectBranches(project, tenant)
+            # Use the cached branch list; since this is a dynamic
+            # reconfiguration there should not be any branch changes.
+            branches = project.unparsed_branch_config.keys()
 
         for branch in branches:
             fns1 = []