diff --git a/internal/api/alerts.go b/internal/api/alerts.go
index cc33613ca..f2d64ba48 100644
--- a/internal/api/alerts.go
+++ b/internal/api/alerts.go
@@ -3,6 +3,7 @@ package api
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"io"
 	"net/http"
 	"net/url"
@@ -199,10 +200,15 @@ func (h *AlertHandlers) UpdateAlertConfig(w http.ResponseWriter, r *http.Request
 	)
 	notificationMgr.SetNotifyOnResolve(updatedConfig.Schedule.NotifyOnResolve)
 
-	// Save to persistent storage
+	// Save to persistent storage. Failure here used to be swallowed (logged
+	// and reported "success"), which led to the in-memory state diverging
+	// from what was actually persisted. On the next restart or config
+	// reload, the override silently vanished. Surface the error so the
+	// client can show a real save-failed signal.
 	if err := h.getMonitor(r.Context()).GetConfigPersistence().SaveAlertConfig(updatedConfig); err != nil {
-		// Log error but don't fail the request
 		log.Error().Err(err).Msg("Failed to save alert configuration")
+		http.Error(w, fmt.Sprintf("Failed to save alert configuration: %v", err), http.StatusInternalServerError)
+		return
 	}
 
 	if err := utils.WriteJSONResponse(w, map[string]interface{}{
diff --git a/internal/api/alerts_test.go b/internal/api/alerts_test.go
index ed2fb4ee9..d786099d5 100644
--- a/internal/api/alerts_test.go
+++ b/internal/api/alerts_test.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
@@ -167,6 +168,43 @@ func TestUpdateAlertConfig(t *testing.T) {
 	assert.False(t, notificationMgr.IsEnabled())
 }
 
+// Regression for #1341: persistence failures used to be silently swallowed
+// (logged but reported as "saved successfully"), so a user setting a 50%
+// per-pool override would see the value stick in memory and revert on
+// reload, with no clue why. Surface the error so the frontend can show a
+// real save-failed signal.
+func TestUpdateAlertConfig_PersistenceFailureSurfacesAsError(t *testing.T) {
+	mockMonitor := new(MockAlertMonitor)
+	mockManager := new(MockAlertManager)
+	mockPersist := new(MockConfigPersistence)
+	notificationMgr := notifications.NewNotificationManager("")
+	defer notificationMgr.Stop()
+
+	mockMonitor.On("GetAlertManager").Return(mockManager)
+	mockMonitor.On("GetConfigPersistence").Return(mockPersist)
+	mockMonitor.On("GetNotificationManager").Return(notificationMgr)
+
+	h := NewAlertHandlers(nil, mockMonitor, nil)
+
+	cfg := alerts.AlertConfig{Enabled: true, ActivationState: alerts.ActivationPending}
+	mockManager.On("UpdateConfig", testifymock.Anything).Return()
+	mockManager.On("GetConfig").Return(cfg)
+	mockPersist.On("SaveAlertConfig", testifymock.Anything).Return(errors.New("permission denied"))
+
+	body, _ := json.Marshal(cfg)
+	req := httptest.NewRequest("POST", "/api/alerts/config", bytes.NewReader(body))
+	w := httptest.NewRecorder()
+
+	h.UpdateAlertConfig(w, req)
+
+	if w.Code != http.StatusInternalServerError {
+		t.Fatalf("status = %d, want 500 on persistence failure", w.Code)
+	}
+	if !strings.Contains(w.Body.String(), "permission denied") {
+		t.Fatalf("response body should expose persistence error, got %q", w.Body.String())
+	}
+}
+
 func TestActivateAlerts_EnablesNotificationManager(t *testing.T) {
 	mockMonitor := new(MockAlertMonitor)
 	mockManager := new(MockAlertManager)