Missing groupby columns while using pandas dataframe

Hi Experts,

I am trying the PoC of a project  via loading data from excel file(just taking excel as an example.) and transform in python dataframe, then load to Power bi. . It runs well in PyDev. But when running in Powerbi, the columns used for groupby are missing. Please could I have your help?

Thanks!

Environment:

Windows 10

Powerbi desktop Version: 2.108.997.0 64-bit (August 2022)
Python3.7
Matplotlib 3.21
Numpy 1.18.4
Pandas 1.0.1

Python codes:

import pandas as pd

import openpyxl as opxls

#===============Read Workgroup Mapping==========

df_orginal=pd.read_excel(open('C:\local\Porject\Configuration\groupby_output_test.xls', 'rb'), sheet_name='groupby_output_test')

print(df_orginal)

print('====================1================================')

df_groupby_date=df_orginal.groupby(by=['Date']).sum()

print(df_groupby_date)

print('======================2==============================')

df_groupby_date_sales=df_orginal.groupby(by=['Date', 'Sales']).sum()

print(df_groupby_date_sales)

print("---------------end------------")

PyDev (groupby) result:

Power BI result

Before groupby, looks fine.

After Groupby[Date]), Date column missing 

After Groupby[Date] and [Sales]), these 2 columns missing