Did you make any other changes to the logstash.yml file in /etc/logstash2?
Particularly, did you give your second logstash a different node.name? And path.config?
$ grep -v ^# logstash.yml | grep [a-z]
node.name: logstash_output
path.data: /var/lib/logstash/output
path.config: /etc/logstash/output/conf.d
config.reload.automatic: true
path.logs: /var/log/logstash/output