Reading IGP data in zarr raises ValueError with shift_averages

[ThomasHaine]

I've rewritten the IGP netcdf data on SciServer into zarr. When I try to open the new zarr data I hit an error with the shift_average variables:

----> 5 od = ospy.open_oceandataset.from_catalog("IGPwinter",local_catalog_file)

~/mambaforge/envs/Oceanography/lib/python3.10/site-packages/oceanspy/open_oceandataset.py in ?(name, catalog_url)
    223 
    224     # Shift averages
    225     shift_averages = metadata.pop("shift_averages", None)
    226     if shift_averages is not None:
--> 227         od = od.shift_averages(**shift_averages)
    228 
    229     # Set OceanSpy stuff
    230     for var in ["aliases", "parameters", "name", "description", "projection"]:

~/mambaforge/envs/Oceanography/lib/python3.10/site-packages/oceanspy/_oceandataset.py in ?(self, averageList)
    996 
    997         for var in self._ds.data_vars:
    998             original_output = self._ds[var].attrs.pop("original_output", None)
    999             if original_output == "average" or var in averageList:
-> 1000                 ds_tmp = self._ds[var].drop_vars("time").isel(time=slice(1, None))
   1001                 self._ds[var] = ds_tmp.rename({"time": "time_midp"})
   1002             if original_output is not None:
   1003                 self._ds[var].attrs["original_output"] = original_output

~/mambaforge/envs/Oceanography/lib/python3.10/site-packages/xarray/core/dataarray.py in ?(self, names, errors)
   3143         Dimensions without coordinates: x, y
   3144         """
   3145         if callable(names):
   3146             names = names(self)
-> 3147         ds = self._to_temp_dataset().drop_vars(names, errors=errors)
   3148         return self._from_temp_dataset(ds)

~/mambaforge/envs/Oceanography/lib/python3.10/site-packages/xarray/core/dataset.py in ?(self, names, errors)
   5945             names_set = {names}
   5946         else:
   5947             names_set = set(names)
   5948         if errors == "raise":
-> 5949             self._assert_all_in_dataset(names_set)
   5950 
   5951         # GH6505
   5952         other_names = set()

~/mambaforge/envs/Oceanography/lib/python3.10/site-packages/xarray/core/dataset.py in ?(self, names, virtual_okay)
   5809         if virtual_okay:
   5810             bad_names -= self.virtual_variables
   5811         if bad_names:
   5812             ordered_bad_names = [name for name in names if name in bad_names]
-> 5813             raise ValueError(
   5814                 f"These variables cannot be found in this dataset: {ordered_bad_names}"
   5815             )

ValueError: These variables cannot be found in this dataset: ['time']

The issue is that the time-like variable for the shift_average data is not called time, it's called time_midp already. I'm confused why this doesn't also cause an issue reading from netcdf, but it doesn't. Ideas on how to fix?