Server response after update with criteria

I have a php server which is serving json data up to my RESTDatasource.

I am seeing errors when performing a ListGrid.Update(record) operation.

In thread http://forums.smartclient.com/showthread.php?t=6619 Isomporphic states
“the most common errors are failure to define a primaryKey, mismatched primary key in the response, or returning a record that no longer matches the current filter criteria.”

The server is returning the record “as-saved”

BUT

In my case, the update I am performing means that the record definitely no longer matches the current criteria.

In this case, does anyone know what the server should return after the update operation?