diff --git a/discovery/manager.go b/discovery/manager.go
index cb08e6b543..51a46ca231 100644
--- a/discovery/manager.go
+++ b/discovery/manager.go
@@ -365,8 +365,10 @@ func (m *Manager) updater(ctx context.Context, p *Provider, updates chan []*targ
 
 func (m *Manager) sender() {
 	ticker := time.NewTicker(m.updatert)
-	defer ticker.Stop()
-
+	defer func() {
+		ticker.Stop()
+		close(m.syncCh)
+	}()
 	for {
 		select {
 		case <-m.ctx.Done():
diff --git a/notifier/manager.go b/notifier/manager.go
index 69ce9b221b..c9463b24a8 100644
--- a/notifier/manager.go
+++ b/notifier/manager.go
@@ -254,7 +254,10 @@ func (n *Manager) targetUpdateLoop(tsets <-chan map[string][]*targetgroup.Group)
 			select {
 			case <-n.stopRequested:
 				return
-			case ts := <-tsets:
+			case ts, ok := <-tsets:
+				if !ok {
+					break
+				}
 				n.reload(ts)
 			}
 		}
diff --git a/scrape/manager.go b/scrape/manager.go
index 7ffce2f38d..c2da455858 100644
--- a/scrape/manager.go
+++ b/scrape/manager.go
@@ -127,7 +127,10 @@ func (m *Manager) Run(tsets <-chan map[string][]*targetgroup.Group) error {
 	go m.reloader()
 	for {
 		select {
-		case ts := <-tsets:
+		case ts, ok := <-tsets:
+			if !ok {
+				break
+			}
 			m.updateTsets(ts)
 
 			select {