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
1519732161,I_kwDOAMm_X85alUXB,7419,Not able to save variable read from h5 file,110075398,closed,0,,,1,2023-01-04T23:31:29Z,2023-01-05T00:18:02Z,2023-01-05T00:18:02Z,NONE,,,,"### What happened?

Hello,
I am not sure that this is a bug but I really don't understand the error message.

I am reading the following [file](https://e4ftl01.cr.usgs.gov/VIIRS/VNP22C2.001/2020.01.01/VNP22C2.A2020001.001.2022041163237.h5) using xarray as 
```
f=xr.open_dataset('VNP22C2.A2020001.001.2022041163237.h5',group='HDFEOS/GRIDS/Cycle 1/Data Fields')
```

However I don't seem to be able to save f to netcdf
```
f[['Date_Mid_Greenup_Phase_1']].to_netcdf('test.nc')


numpy.core._exceptions._UFuncNoLoopError: ufunc 'add' did not contain a loop with signature matching types (dtype('float32'), dtype('<U23')) -> None
```

As far as I can tell there is nothing special with Date_Mid_Greenup_Phase_1
```
f['Date_Mid_Greenup_Phase_1']
<xarray.DataArray 'Date_Mid_Greenup_Phase_1' (phony_dim_0: 3600,
                                              phony_dim_1: 7200)>
[25920000 values with dtype=float32]
Dimensions without coordinates: phony_dim_0, phony_dim_1
Attributes:
    units:        day of year
    valid_range:  [    1 32766]
    long_name:    Date at a mid-greenup phase
```

### What did you expect to happen?

Save variable from hdf file to netcdf

### Minimal Complete Verifiable Example

```Python
import xarray as xr
f=xr.open_dataset('VNP22C2.A2020001.001.2022041163237.h5',group='HDFEOS/GRIDS/Cycle 1/Data Fields')
f[['Date_Mid_Greenup_Phase_1']].to_netcdf('test.nc')
```


### MVCE confirmation

- [x] Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
- [ ] Complete example — the example is self-contained, including all data and the text of any traceback.
- [ ] Verifiable example — the example copy & pastes into an IPython prompt or [Binder notebook](https://mybinder.org/v2/gh/pydata/xarray/main?urlpath=lab/tree/doc/examples/blank_template.ipynb), returning the result.
- [ ] New issue — a search of GitHub Issues suggests this is not a duplicate.

### Relevant log output

_No response_

### Anything else we need to know?

_No response_

### Environment

<details>

commit: None
python: 3.9.15 (main, Nov 24 2022, 08:28:41) 
[Clang 14.0.6 ]
python-bits: 64
OS: Darwin
OS-release: 21.6.0
machine: arm64
processor: arm
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: ('en_US', 'UTF-8')
libhdf5: 1.12.1
libnetcdf: 4.8.1

xarray: 2022.11.0
pandas: 1.5.2
numpy: 1.23.5
scipy: 1.9.3
netCDF4: 1.5.7
pydap: None
h5netcdf: 1.1.0
h5py: 3.7.0
Nio: None
zarr: None
cftime: 1.5.1.1
nc_time_axis: None
PseudoNetCDF: None
rasterio: None
cfgrib: None
iris: None
bottleneck: 1.3.5
dask: None
distributed: None
matplotlib: 3.6.2
cartopy: None
seaborn: None
numbagg: None
fsspec: None
cupy: None
pint: None
sparse: None
flox: None
numpy_groupies: None
setuptools: 65.5.0
pip: 22.3.1
conda: 22.11.1
pytest: None
IPython: None
sphinx: None

</details>
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