diff --git a/src/whylogs/core/metrics/model_metrics.py b/src/whylogs/core/metrics/model_metrics.py
index 7d1eb379d4..e9506d913b 100644
--- a/src/whylogs/core/metrics/model_metrics.py
+++ b/src/whylogs/core/metrics/model_metrics.py
@@ -96,8 +96,9 @@ def merge(self, other):
         """
         if other is None:
             return self
-       
-        model_type =ModelType.UNKNOWN
+
+        model_type = ModelType.UNKNOWN
+
         if (self.model_type not in (ModelType.REGRESSION, ModelType.CLASSIFICATION)):
             if other.model_type in (ModelType.REGRESSION, ModelType.CLASSIFICATION):
                 model_type = other.model_type
@@ -108,7 +109,6 @@ def merge(self, other):
         else:
             model_type = self.model_type
 
-
         return ModelMetrics(
             confusion_matrix=self.confusion_matrix.merge(other.confusion_matrix) if self.confusion_matrix else None,
             regression_metrics=self.regression_metrics.merge(
diff --git a/tests/unit/core/metrics/test_model_metrics.py b/tests/unit/core/metrics/test_model_metrics.py
index d9bd83edb8..ff2d235d57 100644
--- a/tests/unit/core/metrics/test_model_metrics.py
+++ b/tests/unit/core/metrics/test_model_metrics.py
@@ -79,7 +79,7 @@ def tests_model_metrics_to_protobuf_regression():
 
 def test_merge_none():
     metrics = ModelMetrics()
-    metrics.merge(None)
+    assert metrics.merge(None) == metrics
 
 
 def test_merge_metrics_with_none_confusion_matrix():
@@ -95,7 +95,15 @@ def test_merge_metrics_model():
     other.regression_metrics = None
     new_metrics = metrics.merge(other)
     assert new_metrics.model_type==ModelType.REGRESSION
+    assert new_metrics.confusion_matrix is None
 
+    # keep initial model type during merge
+    metrics = ModelMetrics(model_type=ModelType.REGRESSION)
+    other = ModelMetrics(model_type=ModelType.CLASSIFICATION)
+    other.regression_metrics = None
+    new_metrics = metrics.merge(other)
+    assert new_metrics.model_type==ModelType.REGRESSION
+    assert new_metrics.confusion_matrix is None
 
 def test_merge_metrics_with_none_regression_matrix():
     metrics = ModelMetrics()
@@ -111,6 +119,7 @@ def test_merge_metrics_with_none_confusion_matrix():
     other.regression_metrics = None
 
     new_metrics = metrics.merge(other)
+    assert new_metrics.model_type == ModelType.UNKNOWN
 
 
 def test_model_metrics_init():