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
1550792876,I_kwDOAMm_X85cbzis,7463,Coordinates not deep copy,118520620,open,0,,,7,2023-01-20T12:45:52Z,2023-02-13T17:47:22Z,,NONE,,,,"### What happened?

The coordinates are not copied if you perform deepcopy for xarray.
This issue was fixed [before](https://github.com/pydata/xarray/pull/2930). I don't see it, for example, in `xarray 2022.12.0`, but in the latest version the issue is there again.

```python
import xarray as xr

xarr1 = xr.DataArray(
    np.zeros([2]), 
    coords=dict(x=[0.0, 1.0]), # important to use 'float' here! with 'int' it is working fine
    dims=(""x"")
)
print(xarr1.x.data[0]) # 0.0

xarr2 = xarr1.copy(deep=True)
xarr2.x.data[0] = 45
print(xarr1.x.data[0]) # gives 45
```

Interesting, that if your coordinates are `int`, then the issue is gone

### What did you expect to happen?

```python
import xarray as xr

xarr1 = xr.DataArray(
    np.zeros([2]), 
    coords=dict(x=[0.0, 1.0]), # important to use 'float' here! with 'int' it is working fine
    dims=(""x"")
)
print(xarr1.x.data[0]) # 0.0

xarr2 = xarr1.copy(deep=True)
xarr2.x.data[0] = 45
print(xarr1.x.data[0]) # I expect it to be 0.0
```

### Minimal Complete Verifiable Example

```Python
import xarray as xr

xarr1 = xr.DataArray(
    np.zeros([2]), 
    coords=dict(x=[0.0, 1.0]), # important to use 'float' here! with 'int' it is working fine
    dims=(""x"")
)
print(xarr1.x.data[0]) # 0.0

xarr2 = xarr1.copy(deep=True)
xarr2.x.data[0] = 45
print(xarr1.x.data[0]) # gives 45
```


### MVCE confirmation

- [X] Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
- [X] Complete example — the example is self-contained, including all data and the text of any traceback.
- [X] 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.
- [X] 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>
xarray 2023.1.0

python 3.8.10
</details>
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