Errors when Legend field set to Node Reference field

When creating a chart using the views plugin, I need assign the Legend field to a Node Reference field. When doing so the query does not work and below SQL statement is spit out. When I change the legend field to a regular field all is well. Any assistance would be greatly appreciated.

*user warning: Unknown column 'node_data_field_task_project.field_task_project_nid' in 'field list' query: SELECT node_data_field_task_project.field_task_project_nid AS node_data_field_task_project_field_task_project_nid, ROUND(SUM(node_data_field_task_time_total.field_task_time_total_value), 2) AS field_task_time_total_value FROM node node LEFT JOIN term_node term_node ON node.vid = term_node.vid LEFT JOIN term_data term_data ON term_node.tid = term_data.tid LEFT JOIN workflow_node workflow_node ON node.nid = workflow_node.nid LEFT JOIN workflow_states workflow_states ON workflow_node.sid = workflow_states.sid LEFT JOIN content_type_task node_data_field_task_date ON node.vid = node_data_field_task_date.vid LEFT JOIN content_type_task node_data_field_task_time_total ON node.vid = node_data_field_task_time_total.vid WHERE node.type in ('task') GROUP BY node_data_field_task_project.field_task_project_nid ORDER BY node_data_field_task_date_field_task_project_nid ASC LIMIT 0, 10 in /var/www/modules/acquia/views/includes/view.inc on line 755.