diff --git a/libs/core-functions/src/functions/lib/index.ts b/libs/core-functions/src/functions/lib/index.ts
index 1c7df6d20..ecf6a6440 100644
--- a/libs/core-functions/src/functions/lib/index.ts
+++ b/libs/core-functions/src/functions/lib/index.ts
@@ -77,7 +77,7 @@ export type FuncChainResult = {
 };
 
 export type FunctionExecRes = {
-  receivedAt?: any;
+  receivedAt?: Date;
   eventIndex: number;
   event?: any;
   metricsMeta?: MetricsMeta;
diff --git a/services/rotor/src/lib/functions-chain.ts b/services/rotor/src/lib/functions-chain.ts
index 56990a42a..fc73fe8f8 100644
--- a/services/rotor/src/lib/functions-chain.ts
+++ b/services/rotor/src/lib/functions-chain.ts
@@ -288,10 +288,10 @@ export async function runChain(
       const event = events[i];
       let result: FuncReturn = undefined;
       const sw = stopwatch();
-      const rat = new Date(event.receivedAt) as any;
+      const rat = new Date(event.receivedAt);
       const execLogMeta = {
         eventIndex: i,
-        receivedAt: rat && rat != "Invalid Date" ? rat : new Date(),
+        receivedAt: !isNaN(rat.getTime()) ? rat : new Date(),
         functionId: f.id,
         metricsMeta: metricsMeta,
       };
diff --git a/services/rotor/src/lib/metrics.ts b/services/rotor/src/lib/metrics.ts
index 99de26d05..acd99adee 100644
--- a/services/rotor/src/lib/metrics.ts
+++ b/services/rotor/src/lib/metrics.ts
@@ -69,7 +69,8 @@ export function createMetrics(
                 value: JSON.stringify({
                   timestamp: d,
                   workspaceId: m.workspaceId,
-                  messageId: m.messageId,
+                  // to count active events use composed key: messageId_eventIndex_receivedAt
+                  messageId: m.key,
                 }),
               };
             }),
@@ -183,7 +184,7 @@ export function createMetrics(
           return prefix + status;
         })(el);
         buffer.push({
-          key: crypto.randomUUID(),
+          key: el.metricsMeta.messageId + "_" + el.eventIndex + "_" + d.getTime(),
           timestamp: d,
           ...omit(el.metricsMeta, "retries"),
           functionId: el.functionId,