diff --git a/clientapi/routing/register.go b/clientapi/routing/register.go
index 2578180db..0af407587 100644
--- a/clientapi/routing/register.go
+++ b/clientapi/routing/register.go
@@ -91,6 +91,11 @@ func newSessionsDict() *sessionsDict {
 
 // AddCompletedSessionStage records that a session has completed an auth stage.
 func AddCompletedSessionStage(sessionID string, stage authtypes.LoginType) {
+	for _, completedStage := range sessions.GetCompletedStages(sessionID) {
+		if completedStage == stage {
+			return
+		}
+	}
 	sessions.sessions[sessionID] = append(sessions.GetCompletedStages(sessionID), stage)
 }