fix worker allocation

app/src/serving/serving_app.py

@@ -355,6 +355,7 @@ def _predict_job (self, model_type: str, input, params:dict = None):
 
           if result is None:
             try:
+              workername = workername if tndx == 0 else None
               self.postgres_insert_data(
                   "tasks",
                   uuid = taskid,