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/3287#issuecomment-603944176,https://api.github.com/repos/pydata/xarray/issues/3287,603944176,MDEyOklzc3VlQ29tbWVudDYwMzk0NDE3Ng==,5635139,2020-03-25T16:30:20Z,2020-03-25T16:30:20Z,MEMBER,"Re the reordering; that's the case, though it does reorder the dimension, not just the coord (i.e. it's still correctly aligned). Slight change to the original example to demonstrate.

```
In [18]: data = np.arange(2).reshape((2,1,1))
    ...: dims = ['c', 'y', 'x']
    ...:
    ...: d1 = xr.DataArray(data, dims=dims)
    ...: g1 = d1.stack(f=['c', 'x']).groupby('f').first()
    ...: print('Expected dim names:')
    ...: print(g1.coords)
    ...: print()
    ...:
    ...: d2 = xr.DataArray(data, dims=dims, coords={'c': ['R', 'G']})
    ...: g2 = d2.stack(f=['c', 'x']).groupby('f').first()
    ...: print('Unexpected dim names:')
    ...: print(g2.coords)
Expected dim names:
Coordinates:
  * f        (f) MultiIndex
  - c        (f) int64 0 1
  - x        (f) int64 0 0

Unexpected dim names:
Coordinates:
  * f          (f) MultiIndex
  - f_level_0  (f) object 'G' 'R'
  - f_level_1  (f) int64 0 0

In [19]: d2
Out[19]:
<xarray.DataArray (c: 2, y: 1, x: 1)>
array([[[0]],

       [[1]]])
Coordinates:
  * c        (c) <U1 'R' 'G'
Dimensions without coordinates: y, x

In [20]: g2
Out[20]:
<xarray.DataArray (y: 1, f: 2)>
array([[1, 0]])
Coordinates:
  * f          (f) MultiIndex
  - f_level_0  (f) object 'G' 'R'
  - f_level_1  (f) int64 0 0
Dimensions without coordinates: y
```

Yes that second reference looks like the place @spencerahill! ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,490476815
https://github.com/pydata/xarray/issues/3287#issuecomment-603495218,https://api.github.com/repos/pydata/xarray/issues/3287,603495218,MDEyOklzc3VlQ29tbWVudDYwMzQ5NTIxOA==,5635139,2020-03-24T20:44:58Z,2020-03-24T20:44:58Z,MEMBER,This does look weird. A PR would be great.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,490476815