to_zarr append errors when using encoding point in wrong direction

When I try to append to a zarr store created from encoded data it isn't clear that I need to decode the data I want to append.

When I run the attached code, I get an error:

ValueError: failed to prevent overwriting existing key add_offset in attrs. This is probably an encoding field used by xarray to describe how a variable is serialized. To proceed, remove this key from the variable's attributes manually.

Following that error, if I just remove the encoding I can append to the zarr store, but the data isn't encoding correctly.

The fix is to xr.decode_cf(data) and then append.

It would help if the to_zarr append documentation made this clearer.

Example given here:
https://github.com/cgentemann/cloud_science/blob/master/make_zarr/zarr_append_issue.ipynb

Start with the linked zarr_append_issue.ipynb to understand the reported append workflow, then find the xarray documentation for to_zarr append behavior. Clarify that data should be decoded with xr.decode_cf(data) before appending, and confirm that the documented guidance addresses the encoding error.