html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/4120#issuecomment-677939698,https://api.github.com/repos/pydata/xarray/issues/4120,677939698,MDEyOklzc3VlQ29tbWVudDY3NzkzOTY5OA==,46687291,2020-08-20T22:32:01Z,2020-08-20T22:53:14Z,CONTRIBUTOR,"My doubts on this are because self._replace are used elsewhere in the code.

Changing from `_replace` to `copy` causes the tests on coarsen to fail, I am looking more into this now.

------------------

It seems that a condition of copy is that the data shapes match (variable.py line 947).

If I run
```
ds = xr.tutorial.load_dataset(""air_temperature"")
ds.air.coarsen(lat=5)
```
there is no problem, but once I add a `.mean()` to the end 
```
ds = xr.tutorial.load_dataset(""air_temperature"")
ds.air.coarsen(lat=5).mean()
```

The error is 
```
ValueError: Data shape (2920, 5, 53) must match shape of object (2920, 25, 53)
```","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,630062936
https://github.com/pydata/xarray/issues/4120#issuecomment-677926857,https://api.github.com/repos/pydata/xarray/issues/4120,677926857,MDEyOklzc3VlQ29tbWVudDY3NzkyNjg1Nw==,46687291,2020-08-20T21:56:07Z,2020-08-20T21:59:48Z,CONTRIBUTOR,"@dcherian Could this be because the return of `variable.py/coarsen` or is it likely happening earlier in the fx?

```
return self._replace(data=func(reshaped, axis=axes, **kwargs))
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,630062936