fix on the SetCumulativeReward() method in Agent.cs

unity-environment/Assets/ML-Agents/Scripts/Agent.cs

     {
         memory = new float[brain.brainParameters.memorySize];
         stepCounter = 0;
-        CumulativeReward = 0f;
         AgentReset();
     }
 
 
     public void SetCumulativeReward()
     {
-        CumulativeReward += reward;
+        if (!done) {
+            CumulativeReward += reward;
+        }
+        else{
+            CumulativeReward = 0f;
+        }
     }
 
     /// Do not modify : Is used by the brain to collect done.