What happened: datetime was in np.datetime64 formet. When converted t datetime.datetime format it returned an int What you expected to happen: `to get a datetime returned Minimal Complete Verifiable Example:

```python

Put your MCVE code here

import xarray as xr import numpy as np import datetime date_frame = xr.DataArray(dims='time',coords={'time':pd.date_range('2000-01-01',periods=365)},data=np.zeros(365)) print('pandas date range (datetime): ',pd.date_range('2000-01-01',periods=365)[0]) print('dataframe datetime converted to datetime (int): ',date_frame.coords['time'].data[0].astype(datetime.datetime)) print("normal numpy datetime64 converted to datetime (datetime): ",np.datetime64(datetime.datetime(2000,1,1)).astype(datetime.datetime)) output: pandas date range (datetime): 2000-01-01 00:00:00 dataframe datetime converted to datetime (int): 946684800000000000 normal numpy datetime64 converted to datetime (datetime): 2000-01-01 00:00:00 ```

if converted to int, it also gives different lengths of int : date_frame: 946684800000000000 946684800000000 normal datetime64^ Anything else we need to know?:

it is also mentioned in this SO thread appears to be a problem in the datetime64....

numpy version 1.20.0 pandas version 1.2.1

Environment: