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
966669714,MDU6SXNzdWU5NjY2Njk3MTQ=,5691,MultiIndex coordinates loc/sel not working in 0.19.0,13747844,closed,0,,,2,2021-08-11T13:00:19Z,2022-03-17T17:11:42Z,2022-03-17T17:11:42Z,NONE,,,,"**What happened**:
```
TypeError: unhashable type: 'numpy.ndarray'
```

**What you expected to happen**:
No error

**Minimal Complete Verifiable Example**:
Take [this](http://xarray.pydata.org/en/stable/user-guide/data-structures.html#multiindex-coordinates) for example:
```python
import numpy as np
import pandas as pd
import xarray as xr
midx = pd.MultiIndex.from_arrays([[""R"", ""R"", ""V"", ""V""], [0.1, 0.2, 0.7, 0.9]], names=(""band"", ""wn""))
mda = xr.DataArray(np.random.rand(4), coords={""spec"": midx}, dims=""spec"")
mda.loc[{'band': 'R', 'wn': 0.1}]
```

**Environment**:
<details>
xarray: 0.19.0,
pandas: 1.3.1,
numpy: 1.21.1,
</details>","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/5691/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue