diff --git a/metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/sum.rb b/metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/sum.rb
index dfce24379..a858b28ea 100644
--- a/metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/sum.rb
+++ b/metrics_sdk/lib/opentelemetry/sdk/metrics/aggregation/sum.rb
@@ -40,6 +40,8 @@ def collect(start_time, end_time, data_points)
           end
 
           def update(increment, attributes, data_points)
+            return if @is_monotonic && increment < 0
+
             ndp = data_points[attributes] || data_points[attributes] = NumberDataPoint.new(
               attributes,
               nil,
@@ -48,8 +50,6 @@ def update(increment, attributes, data_points)
               nil
             )
 
-            return if is_monotonic && increment < 0
-
             ndp.value += increment
             nil
           end
diff --git a/metrics_sdk/lib/opentelemetry/sdk/metrics/state/metric_stream.rb b/metrics_sdk/lib/opentelemetry/sdk/metrics/state/metric_stream.rb
index 808c64fd0..1d16d44f6 100644
--- a/metrics_sdk/lib/opentelemetry/sdk/metrics/state/metric_stream.rb
+++ b/metrics_sdk/lib/opentelemetry/sdk/metrics/state/metric_stream.rb
@@ -67,7 +67,7 @@ def update(value, attributes)
 
           def aggregate_metric_data(start_time, end_time, aggregation: nil)
             aggregator = aggregation || @default_aggregation
-            is_monotonic = aggregator.respond_to?(:is_monotonic) && aggregator.is_monotonic
+            is_monotonic = aggregator.respond_to?(:is_monotonic) ? aggregator.is_monotonic : nil
 
             MetricData.new(
               @name,