diff --git a/apiserver/bll/event/event_bll.py b/apiserver/bll/event/event_bll.py
index 66e07ae..31c25e8 100644
--- a/apiserver/bll/event/event_bll.py
+++ b/apiserver/bll/event/event_bll.py
@@ -438,10 +438,8 @@ class EventBLL(object):
         last_events contains [hashed_metric_name -> hashed_variant_name -> event]. Keys are hashed to avoid mongodb
         key conflicts due to invalid characters and/or long field names.
         """
-        metric = event.get("metric")
-        variant = event.get("variant")
-        if not (metric and variant):
-            return
+        metric = event.get("metric") or ""
+        variant = event.get("variant") or ""
 
         metric_hash = dbutils.hash_field_name(metric)
         variant_hash = dbutils.hash_field_name(variant)
@@ -486,9 +484,9 @@ class EventBLL(object):
         recent than the currently stored event for its metric/event_type combination.
         last_events contains [metric_name -> event_type -> event]
         """
-        metric = event.get("metric")
+        metric = event.get("metric") or ""
         event_type = event.get("type")
-        if not (metric and event_type):
+        if not event_type:
             return
 
         timestamp = last_events[metric][event_type].get("timestamp", None)
diff --git a/apiserver/tests/automated/test_task_events.py b/apiserver/tests/automated/test_task_events.py
index 3cc3963..d9998ea 100644
--- a/apiserver/tests/automated/test_task_events.py
+++ b/apiserver/tests/automated/test_task_events.py
@@ -193,33 +193,33 @@ class TestTaskEvents(TestService):
 
     def test_last_scalar_metrics(self):
         metric = "Metric1"
-        variant = "Variant1"
-        iter_count = 100
-        task = self._temp_task()
-        events = [
-            {
-                **self._create_task_event("training_stats_scalar", task, iteration),
-                "metric": metric,
-                "variant": variant,
-                "value": iteration,
-            }
-            for iteration in range(iter_count)
-        ]
-        # send 2 batches to check the interaction with already stored db value
-        # each batch contains multiple iterations
-        self.send_batch(events[:50])
-        self.send_batch(events[50:])
+        for variant in ("Variant1", None):
+            iter_count = 100
+            task = self._temp_task()
+            events = [
+                {
+                    **self._create_task_event("training_stats_scalar", task, iteration),
+                    "metric": metric,
+                    "variant": variant,
+                    "value": iteration,
+                }
+                for iteration in range(iter_count)
+            ]
+            # send 2 batches to check the interaction with already stored db value
+            # each batch contains multiple iterations
+            self.send_batch(events[:50])
+            self.send_batch(events[50:])
 
-        task_data = self.api.tasks.get_by_id(task=task).task
-        metric_data = first(first(task_data.last_metrics.values()).values())
-        self.assertEqual(iter_count - 1, metric_data.value)
-        self.assertEqual(iter_count - 1, metric_data.max_value)
-        self.assertEqual(iter_count - 1, metric_data.max_value_iteration)
-        self.assertEqual(0, metric_data.min_value)
-        self.assertEqual(0, metric_data.min_value_iteration)
+            task_data = self.api.tasks.get_by_id(task=task).task
+            metric_data = first(first(task_data.last_metrics.values()).values())
+            self.assertEqual(iter_count - 1, metric_data.value)
+            self.assertEqual(iter_count - 1, metric_data.max_value)
+            self.assertEqual(iter_count - 1, metric_data.max_value_iteration)
+            self.assertEqual(0, metric_data.min_value)
+            self.assertEqual(0, metric_data.min_value_iteration)
 
-        res = self.api.events.get_task_latest_scalar_values(task=task)
-        self.assertEqual(iter_count - 1, res.last_iter)
+            res = self.api.events.get_task_latest_scalar_values(task=task)
+            self.assertEqual(iter_count - 1, res.last_iter)
 
     def test_model_events(self):
         model = self._temp_model(ready=False)