TMSS-717: getSubTasksStartingInThreeMinutes includes subtasks in scheduled and queueing state

MAC/APL/MainCU/src/MACScheduler/TMSSBridge.cc

@@ -106,7 +106,7 @@ Json::Value TMSSBridge::getSubTasksStartingInThreeMinutes()
 
         	for (int32 idx ; idx < result2.size(); idx++)  {
         	    Json::Value item = result2[idx];
-                result.append(item);
+                result = result.append(item);
             }
         }