diff --git a/jeepyb/cmd/update_bug.py b/jeepyb/cmd/update_bug.py
index 31fecf7..3ded116 100644
--- a/jeepyb/cmd/update_bug.py
+++ b/jeepyb/cmd/update_bug.py
@@ -193,6 +193,7 @@ def process_bugtask(launchpad, task, git_log, args):
             # Look for a related task matching the series.
             for reltask in bugtask.related_tasks:
                 if (reltask.bug_target_name.endswith(series) and
+                        reltask.bug_target_name.startswith(args.project) and
                         reltask.status != u'Fix Released' and
                         task.needs_change('set_fix_committed')):
                     set_fix_committed(reltask)