id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
818266159,MDU6SXNzdWU4MTgyNjYxNTk=,4973,NetCDF encoded data not automatically decoded back into original dtype,625462,closed,0,,,2,2021-02-28T17:57:33Z,2022-04-09T01:41:22Z,2022-04-09T01:41:22Z,NONE,,,,"**What happened**:  When reading in an encoded netCDF4 file, encoded variables are not transformed back to their original dtype in the resulting xarray.

**What you expected to happen**:
As with the raw netCDF4 package, if an `xarray.DataArray` of dtype `float64` is encoded into a netCDF4 file as a `float32`, it should be converted back to the original `float64` when the netCDF4 dataset is read back in.

**Minimal Complete Verifiable Example**:

```python
import xarray as xr
import numpy as np
foo = xr.DataArray(np.random.uniform(size=[100,100]).astype(np.float64))
foo.dtype  # float64
ds = xr.Dataset({'foo': foo})
ds.to_netcdf(""foo.nc"", encoding={'foo': {'dtype': 'float32', 'scale_factor': 1.0, 'add_offset': 0.0}})
ds1 = xr.open_dataset(""foo.nc"")
ds1['foo'].dtype  # float32, not float64 as expected
```

**Environment**:

<details><summary>Output of <tt>xr.show_versions()</tt></summary>

INSTALLED VERSIONS
------------------
commit: None
python: 3.7.7 (default, Mar 23 2020, 22:36:06) 
[GCC 7.3.0]
python-bits: 64
OS: Linux
OS-release: 5.4.0-66-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_GB.UTF-8
LOCALE: en_GB.UTF-8
libhdf5: 1.12.0
libnetcdf: 4.7.4

xarray: 0.17.0
pandas: 1.1.5
numpy: 1.19.5
scipy: None
netCDF4: 1.5.6
pydap: None
h5netcdf: None
h5py: 2.10.0
Nio: None
zarr: None
cftime: 1.4.1
nc_time_axis: None
PseudoNetCDF: None
rasterio: None
cfgrib: None
iris: None
bottleneck: None
dask: 2021.02.0
distributed: None
matplotlib: None
cartopy: None
seaborn: None
numbagg: None
pint: None
setuptools: 49.6.0
pip: 20.2.2
conda: None
pytest: None
IPython: 7.21.0
sphinx: None

</details>
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