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
732567105,MDU6SXNzdWU3MzI1NjcxMDU=,4552,UFuncTypeError when reading data from HDF4 file,4762214,closed,0,,,5,2020-10-29T18:46:49Z,2020-11-01T09:28:18Z,2020-11-01T09:28:17Z,NONE,,,,"<!-- Please include a self-contained copy-pastable example that generates the issue if possible.

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**What happened**:  When trying to access numpy.ndarray in a subdataset within a HDF4 file, following error: `UFuncTypeError: Cannot cast ufunc 'multiply' output from dtype('<U32') to dtype('float32') with casting rule 'same_kind'.` Similar error seen when accessing using `netcdf4.Dataset`

**What you expected to happen**: Data to be available as `numpy.ndarray`

**Minimal Complete Verifiable Example**:

```python
# Put your MCVE code here
import requests
import os
import xarray as xr

# download the file
url = 'https://hls.gsfc.nasa.gov/data/v1.4/S30/2020/13/S/D/D/HLS.S30.T13SDD.2020004.v1.4.hdf'
f = os.path.basename(url)
r = requests.get(url, allow_redirects=True)
open(f, 'wb').write(r.content)

# open with xarray and try to access one of the bands of data
ds = xr.open_dataset(f)
ds['B01'].values
```

**Anything else we need to know?**: I've tried the following with netCDF4's Dataset module

```python
from netCDF4 import Dataset
ds = Dataset(f)
ds['B01'][:]
```


**Environment**:

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

INSTALLED VERSIONS
------------------
commit: None
python: 3.6.7 |Anaconda, Inc.| (default, Dec 10 2018, 20:35:02) [MSC v.1915 64 bit (AMD64)]
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 158 Stepping 9, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None
libhdf5: 1.10.5
libnetcdf: 4.7.3

xarray: 0.14.1
pandas: 0.25.3
numpy: 1.17.3
scipy: 1.3.1
netCDF4: 1.5.3
pydap: installed
h5netcdf: None
h5py: 2.10.0
Nio: None
zarr: None
cftime: 1.0.4.2
nc_time_axis: None
PseudoNetCDF: None
rasterio: 1.1.2
cfgrib: None
iris: None
bottleneck: None
dask: 2.9.1
distributed: 2.9.1
matplotlib: 3.0.3
cartopy: 0.17.0
seaborn: None
numbagg: None
setuptools: 44.0.0.post20200106
pip: 19.3.1
conda: None
pytest: 5.3.2
IPython: 7.11.1
sphinx: None


</details>
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