diff --git a/internal/monitoring/pbs_observation_lifecycle_test.go b/internal/monitoring/pbs_observation_lifecycle_test.go
new file mode 100644
index 000000000..99db89533
--- /dev/null
+++ b/internal/monitoring/pbs_observation_lifecycle_test.go
@@ -0,0 +1,98 @@
+package monitoring
+
+import (
+	"testing"
+	"time"
+
+	"github.com/rcourtman/pulse-go-rewrite/internal/models"
+	"github.com/rcourtman/pulse-go-rewrite/internal/unifiedresources"
+	"github.com/rcourtman/pulse-go-rewrite/pkg/metrics"
+)
+
+// Issue #1882: unrelated poll completions must not multiply PBS history, but
+// deduplication must retain a later observation even when its values are equal.
+func TestPBSObservationHistorySurvivesRebuildsAndStoreReopen(t *testing.T) {
+	cfg := metrics.DefaultConfig(t.TempDir())
+	persistent, err := metrics.NewStore(cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		if persistent != nil {
+			_ = persistent.Close()
+		}
+	})
+	monitor := &Monitor{metricsHistory: NewMetricsHistory(1024, 24*time.Hour), metricsStore: persistent}
+	adapter := unifiedresources.NewMonitorAdapter(nil)
+	start := time.Now().UTC().Add(-time.Minute).Truncate(time.Second)
+	var targetID string
+	values := []float64{40, 40, 60}
+	for observation, usage := range values {
+		snapshot := models.StateSnapshot{PBSInstances: []models.PBSInstance{{
+			ID: "pbs-history", Name: "pbs-history", Status: "online",
+			LastSeen:   start.Add(time.Duration(observation) * 10 * time.Second),
+			Datastores: []models.PBSDatastore{{Name: "backups", Status: "available", Total: 1000, Used: int64(usage * 10), Free: int64(1000 - usage*10), Usage: usage}},
+		}}}
+		for rebuild := 0; rebuild < 6; rebuild++ {
+			adapter.PopulateFromSnapshot(snapshot)
+			for _, resource := range adapter.GetAll() {
+				if resource.Type != unifiedresources.ResourceTypeStorage || resource.Storage == nil || resource.Storage.Platform != "pbs" {
+					continue
+				}
+				target := adapter.MetricsTargetForResource(resource.ID)
+				if target == nil || target.ResourceType != "storage" {
+					t.Fatalf("missing storage target: %+v", target)
+				}
+				if targetID != "" && targetID != target.ResourceID {
+					t.Fatalf("target changed: %s -> %s", targetID, target.ResourceID)
+				}
+				targetID = target.ResourceID
+			}
+			if targetID == "" {
+				t.Fatal("missing PBS datastore")
+			}
+			monitor.syncUnifiedStorageMetrics(adapter)
+		}
+	}
+	want := map[string][]float64{
+		"usage": {40, 40, 60}, "used": {400, 400, 600},
+		"total": {1000, 1000, 1000}, "avail": {600, 600, 400},
+	}
+	memory := monitor.GetStorageMetrics(targetID, time.Hour)
+	for metric, expected := range want {
+		points := memory[metric]
+		if len(points) != len(expected) {
+			t.Fatalf("memory %s: got %d points, want %d", metric, len(points), len(expected))
+		}
+		for i, point := range points {
+			timestamp := start.Add(time.Duration(i) * 10 * time.Second)
+			if point.Value != expected[i] || !point.Timestamp.Equal(timestamp) {
+				t.Fatalf("memory %s[%d] = %+v, want %v at %s", metric, i, point, expected[i], timestamp)
+			}
+		}
+	}
+	// Query only after closing and reopening: buffered reads alone are not proof
+	// that the deduplicated observations survived SQLite persistence.
+	if err := persistent.Close(); err != nil {
+		t.Fatal(err)
+	}
+	persistent, err = metrics.NewStore(cfg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for metric, expected := range want {
+		points, err := persistent.Query("storage", targetID, metric, start.Add(-time.Second), start.Add(time.Minute), 0)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(points) != len(expected) {
+			t.Fatalf("reopened %s: got %d points, want %d", metric, len(points), len(expected))
+		}
+		for i, point := range points {
+			timestamp := start.Add(time.Duration(i) * 10 * time.Second)
+			if point.Value != expected[i] || !point.Timestamp.Equal(timestamp) {
+				t.Fatalf("reopened %s[%d] = %+v, want %v at %s", metric, i, point, expected[i], timestamp)
+			}
+		}
+	}
+}