diff --git a/pkg/source/source_client.go b/pkg/source/source_client.go
index 53dc0e34a2e..c4e586335be 100644
--- a/pkg/source/source_client.go
+++ b/pkg/source/source_client.go
@@ -147,28 +147,36 @@ func WithPluginDir(dir string) Option {
 }
 
 func (m *clientManager) Register(scheme string, resourceClient ResourceClient, adaptor requestAdapter, hooks ...Hook) error {
+	scheme = strings.ToLower(scheme)
 	m.mu.Lock()
 	defer m.mu.Unlock()
-	if client, ok := m.clients[strings.ToLower(scheme)]; ok {
+	if client, ok := m.clients[scheme]; ok {
 		if client.(*clientWrapper).rc != resourceClient {
 			return errors.Errorf("client with scheme %s already exist, current client: %#v", scheme, client)
 		}
+		logger.Warnf("client with scheme %s already exist, no need register again", scheme)
+		return nil
 	}
-	m.clients[strings.ToLower(scheme)] = &clientWrapper{
+	m.doRegister(scheme, &clientWrapper{
 		adapter: adaptor,
 		hooks:   hooks,
 		rc:      resourceClient,
-	}
+	})
 	return nil
 }
 
+func (m *clientManager) doRegister(scheme string, resourceClient ResourceClient) {
+	m.clients[strings.ToLower(scheme)] = resourceClient
+}
+
 func (m *clientManager) UnRegister(scheme string) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
-	if client, ok := m.clients[strings.ToLower(scheme)]; ok {
+	scheme = strings.ToLower(scheme)
+	if client, ok := m.clients[scheme]; ok {
 		logger.Infof("remove client %#v for scheme %s", client, scheme)
 	}
-	delete(m.clients, strings.ToLower(scheme))
+	delete(m.clients, scheme)
 }
 
 func (m *clientManager) GetClient(scheme string, options ...Option) (ResourceClient, bool) {
@@ -198,7 +206,7 @@ func (m *clientManager) GetClient(scheme string, options ...Option) (ResourceCli
 		m.mu.Unlock()
 		return nil, false
 	}
-	m.clients[scheme] = client
+	m.doRegister(scheme, client)
 	m.mu.Unlock()
 	return client, true
 }
diff --git a/test/e2e/e2e_test.go b/test/e2e/e2e_test.go
index 467d052669d..83acdb91070 100644
--- a/test/e2e/e2e_test.go
+++ b/test/e2e/e2e_test.go
@@ -68,6 +68,7 @@ var _ = BeforeSuite(func() {
 	rawDfgetVersion, err := pod.Command("dfget", "version").CombinedOutput()
 	Expect(err).NotTo(HaveOccurred())
 	dfgetGitCommit := strings.Fields(string(rawDfgetVersion))[7]
+	fmt.Printf("raw dfget version: %s\n", rawDfgetVersion)
 	fmt.Printf("dfget merge commit: %s\n", dfgetGitCommit)
 
 	if mode == dfdaemonCompatibilityTestMode {