diff --git a/discovery/manager.go b/discovery/manager.go
index d788683adb..3bffe1a9cd 100644
--- a/discovery/manager.go
+++ b/discovery/manager.go
@@ -253,7 +253,8 @@ func (m *Manager) ApplyConfig(cfg map[string]Configs) error {
 	var (
 		wg           sync.WaitGroup
 		newProviders []*Provider
-		keep         bool
+		// triggerSync shows if we should trigger send to notify downstream of changes.
+		triggerSync bool
 	)
 	for _, prov := range m.providers {
 		// Cancel obsolete providers if it has no new subs and it has a cancel function.
@@ -268,7 +269,7 @@ func (m *Manager) ApplyConfig(cfg map[string]Configs) error {
 
 			prov.cancel()
 			prov.mu.RUnlock()
-			keep = true // Trigger send to notify downstream of dropped targets
+			triggerSync = true // Trigger send to notify downstream of dropped targets
 			continue
 		}
 		prov.mu.RUnlock()
@@ -280,7 +281,7 @@ func (m *Manager) ApplyConfig(cfg map[string]Configs) error {
 
 		m.targetsMtx.Lock()
 		for s := range prov.subs {
-			keep = true // Trigger send because this is an existing provider (reload)
+			triggerSync = true // Trigger send because this is an existing provider (reload)
 			refTargets = m.targets[poolKey{s, prov.name}]
 			// Remove obsolete subs' targets.
 			if _, ok := prov.newSubs[s]; !ok {
@@ -313,7 +314,7 @@ func (m *Manager) ApplyConfig(cfg map[string]Configs) error {
 	// See https://github.com/prometheus/prometheus/pull/8639 for details.
 	// This also helps making the downstream managers drop stale targets as soon as possible.
 	// See https://github.com/prometheus/prometheus/pull/13147 for details.
-	if keep {
+	if triggerSync {
 		select {
 		case m.triggerSend <- struct{}{}:
 		default:
diff --git a/scrape/helpers_test.go b/scrape/helpers_test.go
index 5119a4c66b..705abcf4d5 100644
--- a/scrape/helpers_test.go
+++ b/scrape/helpers_test.go
@@ -345,6 +345,10 @@ func setupSynctestManager(t *testing.T, opts *Options, interval time.Duration) (
 	)
 	require.NoError(t, err)
 
+	if interval <= 0 {
+		return scrapeManager, app, cleanup
+	}
+
 	cfg := &config.Config{
 		GlobalConfig: config.GlobalConfig{
 			ScrapeInterval:  model.Duration(interval),
diff --git a/scrape/manager_test.go b/scrape/manager_test.go
index 37570c2f90..e6150224e0 100644
--- a/scrape/manager_test.go
+++ b/scrape/manager_test.go
@@ -1714,3 +1714,127 @@ func TestManager_ScrapeOnShutdown(t *testing.T) {
 		})
 	}
 }
+
+func TestManagerReloader(t *testing.T) {
+	for _, tcase := range []struct {
+		name                    string
+		scrapeOnShutdown        bool
+		discoveryReloadInterval time.Duration
+		updateTarget            bool
+		runDuration             time.Duration
+		expectedSamplesTotal    int
+	}{
+		{
+			name:                 "no scrape on shutdown with default interval",
+			runDuration:          6 * time.Second,
+			expectedSamplesTotal: 1,
+		},
+		{
+			name:                    "no scrape on shutdown",
+			discoveryReloadInterval: 1 * time.Second,
+			runDuration:             1 * time.Second,
+			expectedSamplesTotal:    1,
+		},
+		{
+			name:                 "no scrape on shutdown with default interval and update",
+			updateTarget:         true,
+			runDuration:          12 * time.Second,
+			expectedSamplesTotal: 1,
+		},
+		{
+			name:                    "no scrape on shutdown after ticker",
+			discoveryReloadInterval: 1 * time.Second,
+			updateTarget:            true,
+			runDuration:             2 * time.Second,
+			expectedSamplesTotal:    1,
+		},
+		{
+			name:                 "no scrape on shutdown with default interval after ticker",
+			updateTarget:         true,
+			runDuration:          6 * time.Second,
+			expectedSamplesTotal: 1,
+		},
+		{
+			name:                 "scrape on shutdown without updates",
+			scrapeOnShutdown:     true,
+			runDuration:          2 * time.Second,
+			expectedSamplesTotal: 2,
+		},
+		{
+			name:                 "scrape on shutdown with updates",
+			scrapeOnShutdown:     true,
+			updateTarget:         true,
+			runDuration:          2 * time.Second,
+			expectedSamplesTotal: 2,
+		},
+		{
+			name:                 "scrape on shutdown default interval after ticker",
+			scrapeOnShutdown:     true,
+			runDuration:          6 * time.Second,
+			expectedSamplesTotal: 2,
+		},
+	} {
+		t.Run(tcase.name, func(t *testing.T) {
+			synctest.Test(t, func(t *testing.T) {
+				opts := &Options{
+					ScrapeOnShutdown:        tcase.scrapeOnShutdown,
+					DiscoveryReloadInterval: model.Duration(tcase.discoveryReloadInterval),
+				}
+				scrapeManager, app, cleanupConns := setupSynctestManager(t, opts, 0) // Pass 0 to skip setup config
+				defer cleanupConns()
+
+				cfg := &config.Config{
+					GlobalConfig: config.GlobalConfig{
+						ScrapeInterval:  model.Duration(10 * time.Second),
+						ScrapeTimeout:   model.Duration(10 * time.Second),
+						ScrapeProtocols: []config.ScrapeProtocol{config.PrometheusProto, config.OpenMetricsText1_0_0},
+					},
+					ScrapeConfigs: []*config.ScrapeConfig{{JobName: "test"}},
+				}
+				cfgText, err := yaml.Marshal(*cfg)
+				require.NoError(t, err)
+				cfg = loadConfiguration(t, string(cfgText))
+				require.NoError(t, scrapeManager.ApplyConfig(cfg))
+
+				tsetsCh := make(chan map[string][]*targetgroup.Group)
+				go scrapeManager.Run(tsetsCh)
+
+				// Send initial target to trigger the first reload via the normal flow.
+				initialTargetLabels := model.LabelSet{
+					model.SchemeLabel:  "http",
+					model.AddressLabel: "test.local",
+				}
+				tsetsCh <- map[string][]*targetgroup.Group{
+					"test": {{
+						Targets: []model.LabelSet{initialTargetLabels},
+					}},
+				}
+				synctest.Wait() // Wait for Run to process tsetsCh and for reloader to trigger reload.
+
+				if tcase.updateTarget {
+					newTargetLabels := model.LabelSet{
+						model.SchemeLabel:  "http",
+						model.AddressLabel: "test-updated.local",
+					}
+					tsetsCh <- map[string][]*targetgroup.Group{
+						"test": {{
+							Source:  "test",
+							Targets: []model.LabelSet{newTargetLabels},
+						}},
+					}
+					synctest.Wait() // Wait for Run to process tsetsCh.
+				}
+
+				if tcase.runDuration > 0 {
+					time.Sleep(tcase.runDuration)
+					synctest.Wait()
+				}
+
+				scrapeManager.Stop()
+				synctest.Wait()
+
+				require.Len(t, findSamplesForMetric(app.ResultSamples(), "expected_metric"), tcase.expectedSamplesTotal)
+			})
+		})
+	}
+}