geofield_return_latlon returns "," when no values set.

This is occuring with search_api_location where we have some entities that have a location and some don't. When the entities are being indexed in solr, the ones that don't have a geofield throw an error because the value for the geolocation is ",". I've tracked this down to geofield not doing a good enough check of the data array coming in before sending a response. It checks to see if there is an array but not that the values in the array are set so then solr tries to set the latlon fields to "," which causes an error.