bug fix (#8238)

Author: FeixLiu

paddlenlp/trainer/trainer.py

@@ -413,9 +413,9 @@ def _wrap_amp_model(self, args, model):
             self.scaler = paddle.amp.GradScaler(init_loss_scaling=self.args.scale_loss)
             if self.amp_dtype == "float16" or self.amp_dtype == "bfloat16":
                 if ShardingOption.SHARD_OP in self.args.sharding:
-                    self.scaler = fleet.distributed_scaler(self.scaler)
                     if self.args.amp_master_grad:
                         mix_precision_utils.MixPrecisionScaler(self.scaler)  # retun value has no use
+                    self.scaler = fleet.distributed_scaler(self.scaler)
                 else:
                     # scaler for stage2 and stage3
                     from paddle.distributed.fleet.meta_parallel.sharding.group_sharded_utils import (