delphi 10.3TIdHTTP中文乱码？

delphi 2007正常

RetStr := UTF8Decode(RetStr);

{"result":true,"msg":"同步成功1/1条}

delphi 10.3不正常

RetStr := UTF8Decode(RetStr);

{"result":true,"msg":"同步成功1/1�?}

注意下面代码的中文注释

HTTP := TIdHTTP.Create(nil);
        HTTP.HandleRedirects := True;
        LoadOpenSSLLibrary;
        HTTP.Request.CustomHeaders.AddValue('X-LINE-ChannelId', PlatformID);
        HTTP.Request.CustomHeaders.AddValue('X-LINE-ChannelSecret', MerchantID);
        HTTP.Request.ContentType := 'application/json';
        HTTP.Request.CharSet := 'UTF-8';
        try
          try
            JsonData := SO;
            JsonData.s['productName '] := xMemo;   { TODO : 中文字是這行 }
            JsonData.i['amount'] := StrtoInt(xPay) ;
            JsonData.s['currency'] := 'TWD'; 
            JsonData.s['orderId'] := xorderId;
            JsonData.s['oneTimeKey'] := xbuyerID;
            JsonData.s['capture '] := 'true';

            Source := TStringStream.Create(JsonData.AsString, 65001);

            { TODO : 上面这行必须得用stream 病使用65001就好.....POST的时候参数送Stream，不要送TStrings }

           try
              HTTP.IOHandler := FHandlerSSL;
              try
                mCMVstr := HTTP.Post( 'https://'+FLineConnectStr+'/v2/payments/oneTimeKeys/pay', Source); 
              except
               
                if not Result then


                begin
                  exit;
                end;
              end;