Model based delete is failing

with 500 error and message

{"requestError":{"serviceException":

{"messageId":"SVC3002","text":"Error writing output performing %1 on %2 (msg=%3) (ec=%4)","variables":["POST Search","getModelQueryResponse","Unexpected error reading/updating database:java.lang.IllegalStateException: Vertex with id 984154232 was removed.","ERR.5.4.5105"]}

}}