diff --git a/AsbCloudInfrastructure/Background/PeriodicWorks/WorkDataSaubStat.cs b/AsbCloudInfrastructure/Background/PeriodicWorks/WorkDataSaubStat.cs
index d6b4a257..69e510f9 100644
--- a/AsbCloudInfrastructure/Background/PeriodicWorks/WorkDataSaubStat.cs
+++ b/AsbCloudInfrastructure/Background/PeriodicWorks/WorkDataSaubStat.cs
@@ -40,13 +40,15 @@ namespace AsbCloudInfrastructure.Background.PeriodicWorks
             if (!idTelemetries.Any())
                 return;
 
-            var stats = await db.Set<DataSaubStat>()
+            var statsQuery = await db.Set<DataSaubStat>()
                 .Where(s => idTelemetries.Contains(s.IdTelemetry))
+                .ToArrayAsync(token);
+
+            var stats = statsQuery
                 .GroupBy(s => s.IdTelemetry)
-                .ToDictionaryAsync(
+                .ToDictionary(
                     g => g.Key,
-                    g => g.OrderByDescending(s => s.DateEnd).First(),
-                    token
+                    g => g.OrderByDescending(s => s.DateEnd).First()
                 );
 
             foreach ( var idTelemetry in idTelemetries)
@@ -92,6 +94,7 @@ namespace AsbCloudInfrastructure.Background.PeriodicWorks
         {
             var indexStart = 0;
             var indexEnd = 0;
+            var result = new List<DataSaubStat>();
             foreach (var operation in detectedOperations)
             {
                 indexStart = Array.FindIndex(telemetryDataSaub, indexEnd, t => t.DateTime >= operation.DateStart);
@@ -103,14 +106,21 @@ namespace AsbCloudInfrastructure.Background.PeriodicWorks
 
                     var subset = telemetryDataSaub.AsSpan(indexStart, length + 1);
                     var stats = CalcStats(operation, subset);
-                    foreach (var stat in stats)
-                        yield return stat;
+                    result.AddRange(stats);
+                }
+                else
+                {
+                    indexStart = 0;
+                    indexEnd = 0;
                 }
             }
+            return result;
         }
 
         private static IEnumerable<DataSaubStat> CalcStats(DetectedOperation operation, Span<TelemetryDataSaub> telemetryDataSaub)
         {
+            var result = new List<DataSaubStat>();
+
             var indexStart = 0;
             for (var i = 1; i < telemetryDataSaub.Length; i++)
             {
@@ -123,9 +133,11 @@ namespace AsbCloudInfrastructure.Background.PeriodicWorks
                     var span = telemetryDataSaub.Slice(indexStart, length);
                     indexStart = i;
                     var stat = CalcStat(operation, span);
-                    yield return stat;
+                    result.Add(stat);
                 }
             }
+            
+            return result;
         }
 
         private static DataSaubStat CalcStat(DetectedOperation operation, Span<TelemetryDataSaub> span)