diff --git a/checker/worker/metric_events.go b/checker/worker/metric_events.go
index 67c686115..c7a5d44e5 100644
--- a/checker/worker/metric_events.go
+++ b/checker/worker/metric_events.go
@@ -84,7 +84,9 @@ func (manager *WorkerManager) handleMetricEvent(pattern string) error {
 	start := time.Now()
 	defer manager.Metrics.MetricEventsHandleTime.UpdateSince(start)
 
-	manager.lastData = time.Now().UTC().Unix()
+	now := time.Now().UTC().Unix()
+	manager.lastData = now
+
 	triggerIds, err := manager.Database.GetPatternTriggerIDs(pattern)
 	if err != nil {
 		return err
diff --git a/checker/worker/scheduler.go b/checker/worker/scheduler.go
index 77eb14b98..c1b5f46c5 100644
--- a/checker/worker/scheduler.go
+++ b/checker/worker/scheduler.go
@@ -84,7 +84,7 @@ func (ch *scheduler) triggerScheduler(stop <-chan struct{}) error {
 func (ch *scheduler) scheduleTriggersToCheck() error {
 	err := ch.validateSource()
 	if err != nil {
-		ch.manager.Logger.Info().
+		ch.manager.Logger.Warning().
 			Error(err).
 			String("cluster_key", ch.clusterKey.String()).
 			Msg("Source is invalid. Stop scheduling trigger checks")
diff --git a/checker/worker/trigger_handler.go b/checker/worker/trigger_handler.go
index 1b2e617ac..817b6e23b 100644
--- a/checker/worker/trigger_handler.go
+++ b/checker/worker/trigger_handler.go
@@ -47,7 +47,6 @@ func (manager *WorkerManager) handleTrigger(triggerID string, metrics *metrics.C
 
 func (manager *WorkerManager) handleTriggerInLock(triggerID string, metrics *metrics.CheckMetrics) error {
 	acquired, err := manager.Database.SetTriggerCheckLock(triggerID)
-	defer manager.Database.DeleteTriggerCheckLock(triggerID) //nolint
 
 	if err != nil {
 		return err
@@ -57,6 +56,8 @@ func (manager *WorkerManager) handleTriggerInLock(triggerID string, metrics *met
 		return nil
 	}
 
+	defer manager.Database.DeleteTriggerCheckLock(triggerID) //nolint
+
 	startedAt := time.Now()
 	defer metrics.TriggersCheckTime.UpdateSince(startedAt)
 
diff --git a/checker/worker/worker_manager.go b/checker/worker/worker_manager.go
index 02cec4676..2b1a64b8a 100644
--- a/checker/worker/worker_manager.go
+++ b/checker/worker/worker_manager.go
@@ -87,11 +87,11 @@ func (manager *WorkerManager) makeSourceValidator(clusterKey moira.ClusterKey) (
 func (manager *WorkerManager) validateGraphiteLocal() error {
 	now := time.Now().UTC().Unix()
 
-	if manager.lastData+manager.Config.StopCheckingIntervalSeconds < now {
+	if manager.lastData+manager.Config.StopCheckingIntervalSeconds > now {
 		return nil
 	}
 
-	return fmt.Errorf("graphite local source invalid: no metrics for %d second", manager.Config.StopCheckingIntervalSeconds)
+	return fmt.Errorf("graphite local source invalid: no metrics for %d second", now-manager.lastData)
 }
 
 func (manager *WorkerManager) startCheckerWorker(w *scheduler) error {